Both players could be key to the Edinburgh club’s ambitions in the Premiership next season, provided they complete a predicted ascent back to Scotland’s top division.
Boyce is the Championship’s top goalscorer on 11 and has rippled netting 14 times in 27 games for club and country so far this season.
Gnanduillet is a January signing who is nearing full fitness but the giant Frenchman’s movement and intelligence are already dovetailing with Boyce’s craft.
The Northern Irishman feels more comfortable as part of a two-man attack, such as last weekend when he and Gnanduillet stood out in the 2-1 win against Dundee.
“It was good playing beside Armand in a two up front. Any time I am away with Northern Ireland and at Ross County, I have played in a two,” he said.
“It's good to have the options of playing one or two and Armand is a big presence. You saw at the first goal against Dundee, he is composed on the ball too and put in a good delivery [for Andy Halliday’s header].
“I enjoyed playing in a partnership with him and it just means I only need to run one channel, not two. I do like playing with a partner and it doesn't happen in football that much now.
“We have been working together gradually on some partnership things, like where we should be in the shape. But Saturday is the most important time for a partnership to develop.
“When it's competitive and it's off the cuff, and you react off what defenders do, you get a real benefit from playing together. Hopefully with the more minutes we get, that can develop.”
One might imagine communication is a challenge between the respective Northern Irish and French accents. “It's not Armand I’m worrying about. It's the Scottish boys,” laughed Boyce.
“I have to say everything twice and slow down. All I hear is ‘what?' everytime I speak. My accent is worse than anyone's.”
His compatriot, Michael Smith, can always translate. “Aye, he's posher than me! He's slightly more country so he's easier to understand.”
Smith and Boyce are expected to be named in the Northern Ireland squad for World Cup qualifiers later this month. Ian Baraclough’s side travel to Italy and host Bulgaria as their Qatar 2022 campaign begins. A friendly with the USA is sandwiched in between.
If called upon, both players stand to miss Hearts’ Scottish Cup trip to Brora Rangers on March 23 and the Championship fixture against Queen of the South at Tynecastle four days later. Smith is suspended for the cup tie in any case.
However, Boyce’s participation may ultimately be in the hands of Mother Nature. “The games we've got are massive but my missus is due in about six days so it'll be touch and go,” smiled Boyce.
“I'll have to wait and see what happens with the squad and then take it a day at a time to see if I can make any of the games.
“When I had my daughter, it was when Euro 2016 was on and obviously I didn't get picked for the Euros. Then during the first game my daughter was born so I'm glad I didn't experience it then because it would have been a tough decision to come home.
“Well, not a tough decision obviously because it was my first child! But it's an awkward position to be in and I'll obviously be doing everything I can to be able to play in the games.”
He and Baraclough have already discussed the issue and the player is grateful to have the full backing of his national coach.
“I spoke to him a couple of months after we found out she was pregnant. Because it's that close to the Italy game, it's his decision with the squad. We've had conversations but we just have to leave it and see what happens and when the baby decides to come.
“He's a top man. I'd come up against him when he was at Motherwell and he always comes over and talks to you after the games. He’s friendly and easy to talk to.
“We obviously didn't win the play-off final but the two games after that, I thought we did really well using different formations. I was playing too so that's a positive!
“He always keeps in contact and it’s good to have someone who goes out of their way to make sure you're doing well.”
Travelling is a major concern for players and clubs given the risks of Covid 19. Leaving a biosecure club bubble to join an international group means mixing with others but testing is done rigorously throughout.
Boyce explained that medical experts at the Northern Ireland Football Association take care of the tests to let players focus purely on football. It doesn’t get much more daunting than an opening World Cup qualifying tie against Italy in Parma.
“It's a bit strange with all the traveling,” said Boyce. “I don't really know what's happening with the rules and stuff but we know it's a big start to our World Cup campaign and it doesn't get any bigger than Italy away.
“We just need to concentrate on that and forget about all the stuff off the field. All the docs have been brilliant. I don't think we've had anyone calling off after a test. It's all been perfect so far so just need to keep trusting in them.”