Clarke has revealed he already “more or less” knows what his starting line-up will be for the Group D opener against Czech Republic at Hampden on June 14.
The Scots will leave Glasgow on Thursday for a training camp in Spain from where they will travel to pre-tournament friendlies against Netherlands on June 2 and Luxembourg on June 6.
While Clarke will give all of his players the opportunity to stake their claims, he doesn’t expect to stray too far from the settled side he has in his mind once the competition gets underway.
“I know (the team to face Czech Republic), more or less,” said Clarke. “I can't say I've completely nailed down the 11, because that would be wrong.
“Boys are coming into the squad that will be going for hell for leather to show me they deserve to start.
“But if I go on what I've seen before, yeah, I know who I'd want in the starting 11. But we've got a training camp this time.
“It's not a case of just having two days with the players. We have ten days in Spain, two friendly matches, so a lot of players have an opportunity to change my mind.
“In our last game against the Faroe Islands in March, I put some boys on the pitch who hadn’t been involved in the previous two games just to get them off the bench, give them a cap and make them feel involved. They then go away with a good feeling.
“But in a tournament situation, it is slightly different to that. You will be going more or less flat out with your first 11, give or take some injuries or whatever, with maybe one or two little tactical tweaks.
“Out of the 26, there are maybe eight to ten players that ought not get any time on the pitch.
“But I would like to think they are grateful to be involved in the first tournament for such a long time.”
Maintaining a positive environment and keeping every player happy, especially those who may not get any game time during the tournament, could be one of the biggest challenges facing Clarke whose squad will spend at least four weeks together – even longer if Scotland progress from the group stage.
“I won’t know (how difficult that will be) until we get there, to be honest,” he said.
“In the shorter camps that we have had in my time with them, we have managed the squad well.
“I know most of the squad well, although obviously I don’t yet know the three younger lads – Nathan Patterson, Billy Gilmour and David Turnbull – who are coming in, but I’m told they are all good lads.
“It’s important to have good people in your squad. I have good leaders in the squad too, the senior players will be good. So I don’t have too many worries about it to be honest.
“That’s probably a question for after the tournament and I’ll tell you how it went.”