The Bucks, who play their seventh of 10 friendly matches at Rushall tonight, have given a handful of unattached players the chance to impress as they prepare for the National League North season.
But with the campaign now under three weeks away Cowan is set to streamline the group.
“The reason there’s 10 pre-season games is because we needed to get something into the players’ legs,” he explained.
“We feel like we’ve done that now. We’ll now start to whittle the squad down, either add or release a few trialists and try to thin it out a little bit because the lads will start to need 90 minutes now, that’s important for the opening day.
“We’re building really well, we’re really happy with where we are, everybody’s on point, maybe a little ahead.”