The Light Blues began with a particularly youthful lineup which included six players who are still eligible to play at Under-18s level.
Among those included from the off were Calum Adamson and Chris Eadie, both born in 2007, with the former making his B Team debut for the club.
There were also appearances off the bench for fellow 2007-born duo Jack Wyllie and Cameron Scott, as well as Findlay Curtis and Kieron Willox who have spent the majority of the campaign with the Under-18s side.
Speaking to RangersTV after the triumph, McCallum commented: “The squad was a little bit different today. It was one of the most changeable squads that we’ve had in terms of age range.
“You look at Cole [McKinnon] and Robbie [Fraser] who were clearly the older ones in the group and who have been here for a bit of time now, fluctuating between different stages of their journey.
“Then you look at the number of younger ones and 2007-born players. There was quite an age range, and it was important that we found a way as a team to have a performance.
“It’s important because opportunities tend to come whether it be by their performance, which is the first thing we look at, or player movement, which we look at next.
“We’ve had a couple of situations develop in the last week: Darren McInally picking up another injury which is disappointing for him, and us all, because he was at a stage where he was really finding his way back.
“But that opens the door for someone like Calum Adamson today who started his first game. He was excellent and didn’t look younger than the group that was there.
“He was really competitive, showed quality, and we took him off because at that point of the game he showed what he was capable of doing in this environment.”
Both goals arrived in the second half for Gers B as they got their rewards for an assured display on both sides of the ball.
The opening goal arrived from the foot of Kristian Webster as the defender lashed home from a corner, before James Graham doubled his side’s advantage five minutes later with a tremendous individual effort.
McCallum added: “In terms of the first half, there was probably the two big chances that we should have taken.
“I thought we got more of a grip on the performance as the game went on; we controlled and continued to create.
“The biggest thing at half-time was that they felt they had to keep fighting in the first half, and really we had to compete in moments where control was a little bit loose for both sides.
“We could have put the game to bed before half-time with the chances that we had, but we didn’t.
“We’ve obviously scored two good goals in the second half to put us into a position of, not comfort per se, but to a point where we didn’t allow Bolton back into the game.”