Apertura 60EDR vs 72EDR with DSLR

Well, the rule of thumb is to keep the weight of your camera, scope, and guiding gear below half of the mount's rated weight capacity.  So the 72EDR will probably put you over that.  Having said that, I know that some folks exceed that rule of thumb and still get good results.   There isn't a huge difference in terms of focal length on the two scopes so your FOV will probably be very similar.  I use a 400mm prime telephoto lens with a canon 80D (it has the same APS-C size sensor as your T7i) and, for reference, the Andromeda Galaxy nearly fills the frame from corner to corner.  So I would expect the 60EDR to give you a slightly wider FOV and the 72EDR to be slightly tighter.  That is assuming you use a non-reducing flattener with the scope.  One suggestion, if you use Stellarium, you can plug in your camera and scope specs and preview how various targets will look.  I hope that is helpful to you.  Happy New Year, and clear skies!

Bill