Hey man, I did this job just two weekends ago and I am a very novice car wrencher dude. I had the same issue with the drivers side but I managed to succeed by doing them one at a time and taking it very slow. Use the fuel lines in the centre as a kinda fulcum and rock the manifold up on the front and rear.
(so the rear will be down pressed against the tgv when you're doing the front and vice versa)
What I did for the drivers side:
pulled up on the mainfold so I could get an allen key (the biggest one I have - just a smidge taller than the new gasket) in where one of the bolts (TGV -> intake) sit at the very front (dont put this between the TGV-intake, only at the bolt hole). I then had just enough room to pick out the gasket and I could put the new gasket on the tgv and use the manifold to seal it in. I used the allen key as a lever to push up on the manifold when I needed more room. Do the same thing for the rear. Its very tight, and I didn't think i'd have enough room because of the fuel lines, but rocking it up allows you to have enough room. You can pull pretty hard against those lines as well. There is enough room.
IT CAN BE DONE