Zip up then suit up, or the other way around?

Hello! I got a bit carried away at the weekend when shopping for boots, ended up walking away with a 2-piece RST suit. Massively overkill, but it's comfortable and safe and therefore I think it's worth it!

Anyway, how the hell do you get it on without pulling a muscle or slipping a disk?! Do you put on the two pieces and then zip them together, or zip them together and perform some magic trickery to get in?

I've managed both, just seeing what others thought!