A fellow pilot with an Arcus hit on an excellent solution and I'd mention his name but maybe he'd prefer not. He's probably reading this?

Take a stout pry bar along in the back seat and insert it under the left hand grab handle and then over the canopy frame cross bar that lies a couple inches in front of the grab handle. Prying up on the bar will allow the three locking pins to slide home.

Of course keeping the canopy as cool as possible helps. A white canopy cover is better than the common IR absorbing aluminum ones. If you have the latter, throw a white bed sheet over it.

Karl Striedieck