I have a long sleeve top but its not baggy . I wouldnt think you would want it baggy cause it could collect water if you suit gets flushed
thats what i was thinking, but i know there are some people out there who say "my suit only lets in a teaspoon of water!" or something along those lines, thats what i was mainly referring to. but i definitely wouldn't try it if the suit is prone to flushing or doesn't have great seams
I imagine you could pull it off, that stuff is like 1 mm neoprene isn't it?
I've rocked a rash guard under my suit, but once it gets really cold it almost becomes counter productive. The reason I say that, and this is only in my experience, the neck of the rash guard tends to break the seal of the wetsuit around my neck. The result is I get flushed way easier with a rash guard on than without it.
You might also want to check out one of those vest/hoods that you can wear under your suit. Even though the suit might flush a little more, you won't feel it and the extra neoprene on the core area makes a huge difference. I haven't worn one but I have a friend who does all winter. He said it's more restrictive on his breathing, but the trade off is he is always the last one to want to get out.