Wearing Under Armour makes it much easier to get out of your suit, especially if you've been sweating.
Oh I did such a dance to get my A* on when I got it, I called to return it but it was the right size. Wound up doing some yoga poses and lots of stretching on the first trackday and now it feels like butter. It stretches a good 10lbs plus skipping beer and wings helped for a few days. Get a good undersuit like the one from www.motodracing.com which will also protect the leathers from sweat and grime and allow you to slide in easier.
A* i know sells the under suit to get in & out quicker but like you mentioned I wear a long sleeve underarmor shirt & compression shorts and I'm in & out of the suit on my own with no help.
Rule of thumb: Suit should be snug on arms and legs, but not constrict movement. It should be non-constricting when you are tucked in on the bike. If it feels like your GF/BF/SO is nicely squeezing your boys when you stand, it's probably right. If it feels like your GF/BF/SO is stomping on them when you stand, it's probably too tight. And if you can't tell the difference, you probably need to be more adventurous.