Ahead of the club's six-day stay in Scotland, McCall's men picked up their first friendly win this summer thanks to goals from Billy Clarke and Paul Anderson in the opening half at Gateshead International Stadium.
Speaking after the victory over Gateshead, McCall said: "It was another good work-out for the lads - a lot of the boys got 60-70 minutes.
"I was very happy with some of the football we played, especially in the first half.
"At this stage of the summer, it is all about building up the fitness levels and getting that rustiness out of their system and getting the lads used playing games again.
"There were some good balls into the box, some good opportunities created, and two good goals. We also defended reasonably well also, so overall it was a pleasing afternoon.
"As we've told the lads before, we don't want to be robotic this season. We don't want teams to know exactly how we are going to play all of the time.
"We need that flexibility in our game to be able to mix things up. We will need more than just a Plan A during the season.
"With the players we have in the side now, plus the extra players we hope to bring in, we will have that ability to be more than just a one-trick pony."
Fresh from completing his season-long loan move from Huddersfield Town just twenty-four hours earlier, new Bantams striker Jordy Hiwula was given his first outing in City colours as a second half substitute at Gateshead.
McCall added: "He can mix things up, he can come short for the ball and he can also get in behind and stretch the game.
"His record in youth football and in the league tells you that he is a finisher.
"This is an ideal club for Jordy to be able to show everybody what he can do.
"I think we still need another striker in as well, and other areas like central midfield also need strengthening, but we're still looking and work is being done."
Following the win at Gateshead, McCall's squad continued north on Saturday to their hotel base in St Andrews.
During their stay in Scotland, City will play away at St Johnstone in their next pre-season friendly fixture.
The Bantams are due back in Bradford on Friday ahead of their first match at Valley Parade this summer against Premiership side Burnley the day after.
McCall said: "All due respect to the teams we have played so far but the quality of opposition we face will go up now when we face St Johnstone and then Burnley this week.
"Nathan Clarke got the full 90 minutes under his belt at Gateshead so we might look to give a couple more of them the whole match on Tuesday.
"We will have a look at all the options, however, and see what we come up with for Tuesday."