The two strikers were amongst the goals in the most recent outing, a 7-0 friendly win at New Mills, with Cofie scoring a hat-trick and Keane bagging a brace.
Both are likely to have the responsibility of firing the bullets for the second-string and boss Joyce is hoping they pick up good habits at this level.
"There's certainly a lot of things that are very good with Keane and Cofie," he told ManUtd.com. "But there's a lot of things they've got to work on and develop. They're both hard-working kids and I'm looking forward to working with them."
However, Joyce does not feel any shoot-out between the pair in terms of a race to be top scorer would prove beneficial to the side as a whole.
"I don't think you're necessarily looking for that," he reasoned. "As I want them to be unselfish for the team - if there's a better solution for the team.
"It doesn't matter who scores but you'd expect them both to be amongst the goals."
The Reserves are next in action on Thursday when they face Swansea at Altrincham's Moss Lane, with the match live on MUTV.