Scheming Imran Sakur, 35, laughed and joked with his intended victim just minutes before the shooting plan was put into effect.
He also pretended to chase the black-clad gunman who sprinted away after blasting businessman Tony Demarco, 63, in the back of the head at close range.
But at the High Court in Edinburgh today a jury found Sakur guilty of hatching the murder plot.
The hit-man hired by Sakur, his getaway driver and another man who helped set up the assassination bid are also in custody facing long prison sentences.
Mr Demarco cried "Oh you b******" as he was shot after strolling to his distinctive silver Mercedes.
A trial heard he was lucky to be alive and a bullet which bounced off his skull is still lodged in his cheek.
The jury saw how Sakur laughed and joked with "Italian Tony" on the steps of the Gala Maybury Casino on the night of 3 June 2008.
But CCTV footage from the casino's security cameras also showed Sakur with his mobile phone to his ear as soon as Mr Demarco's back was turned.
This was the signal for gunman Jamie Robertson, 25, to move in and pull the trigger, before speeding away in a maroon Peugeot with Francis McGlone, 39, at the wheel.
During the days leading up to the shooting, Sakur's messages had been relayed through Craig Kelbie, 35 – who also calls himself Craig Wallace – in an attempt to avoid being linked the planned murder.
Eye-witnesses in the Maybury area gave widely differing descriptions of the gunman and picked out the wrong man at identity parades.
But detectives who set up "Operation Muster" to catch the would-be killer were left with two vital pieces of evidence.
A trawl through hours of security camera film showed McGlone's car driving around the casino area in a suspicious way, and even revealed the number-plate.
And a pain-staking search also found a spend cartridge lying in the road.
After a dawn raid on his Paisley home three weeks later, McGlone named body-builder Robertson as the gunman in an "off the record" chat with detectives – comments he later tried to withdraw.
He also claimed he had been at home on the night of the shooting but a call to his mobile phone from his then fiancee helped destroy his alibi.
Police raided another Paisley house where Robertson had been staying and found a box of cartridges hidden in the loft. They matched the 8mm shell case found at the Maybury and four were missing from the box of 50.
Advocate depute John Scullion, prosecuting, made the chilling allegation that Robertson had hung onto the ammunition in the hope of completing the contract killing, and made a further visit to Mr Demarco's home.
Mr Scullion suggested there had also been a previous attempt to track down Mr Demarco when Robertson hung around the businessman's house in Danderhall, Midlothian. Robertson failed to spot Mr Demarco because he was not in his usual silver Mercedes.
Mobile phone records linked Robertson first to Kelbie – Robertson's girlfriend's brother – and then to Sakur, Kelbie's landlord.
Detectives confronted Sakur with a tip-off that Mr Demarco had a price of 20,000 on his head – later dropped to 10,000 because the businessman survived and eventually part-paid in dodgy vodka rather than cash.
The motive was said to be debts owed to Mr Demarco.
"That is not me. I don't owe him a penny," replied Sakur. "Ask him yourself." And during the trial he claimed it was another man, Shahid Aslam, who owed Mr Demarco hundreds of thousands of pounds and wanted him dead.
In court, Mr Demarco also repeatedly denied that Sakur owed him money. Other witnesses spoke of Sakur's money worries and named Mr Demarco as one of his creditors.
Sakur's high-rolling gambling had cost him 40,000 at the Maybury casino, the trial heard.
And around the time of the shooting he was also involved in an unconnected civil court action over a 1.5 million deal which had gone sour – and faced allegations that he had received a pay-off to persuade a buyer to sign up for property in Dundee's Dens Road Market.
Mr Demarco, who described himself as a sandwich bar owner, was supposed to be putting Sakur under pressure.
The trial heard that Sakur approached his tenant Kelbie in the belief that he knew "gangsters" who could persuade Mr Demarco to back off. The name of veteran underworld figure Paul Ferris cropped up.
Soon after the shooting, Kelbie and his family were sunning themselves in Turkey, staying at a villa there owned by Sakur.
Both Dakue and Kelbie agreed during the trial that they had arranged for Mr Demarco to get a warning but insisted it was to be no more than "a slap."
Re-living the painful ordeal in court, father-of-two Mr Demarco, said: "I don't know who shot me."
He told the trial: "As I went to open my car door I heard a bang and felt a thud behind my ear, my right ear."
Mr Demarco continued: "I turned. I tried to get away from the pain while clutching my head, then walked round the car to the pavement."
He added: "I thought I had been assaulted."
Mr Demarco said he had not been aware of anyone behind him and had not heard any footsteps.
Someone came from the casino with a chair and tried to get him to sit down and someone put padding on the wound. Then an ambulance arrived and he was taken to hospital.
"I was told I had a gunshot wound at the back of my right ear and it had lodged in my cheek."
Mr Demarco said the bullet was still there. Medics told him that because it was so close to the carotid artery and important nerves it was too dangerous to try to remove it.
No weapon was ever recovered but police firearms expert Ronald Withers told the trial it was probably a converted starting pistol.
With the barrel bored out, a blank cartridge in the breech could be made to discharge a home-made bullet loaded into the muzzle, he said.
The pistol would not have the power of a "real" firearm.
Labourer McGlone, of Lochfield Crescent, Paisley, bricklayer Robertson, of Stock Street, Paisley, property developer Sakur, of Elcho Drive, Broughty Ferry, Dundee, and unemployed panel beater Kelbie, of Saggar Street, Dundee, face sentence on 9 February in Kilmarnock when background reports have been prepared.
All were found guilty of conspiracy to murder and attempted murder – by majority in the case of Sakur and McGone and unanimously for Robertson and Kelbie