My old Stratoliner was the easiest I've seen. Unlock it with the key,,, Pulled right off. It 'Clicked' back into place.
That's a bit odd that your MC modded seat was tougher to put back on,,, Maybe they changed it's profile / added some foam in an area?
Even an 100% OEM Wing seat isn't the easiest to put on,,, The good thing is, hopefully, one doesn't have to take it on and off much.