I use Faber 12's, never noticed any problem with trim with them. I've got a Dive Rite classic wing on it, nice and simple design. Everyone else has copied it and "improved" it but it still really is a very nice wing. And for the money about the best you can get.
I use a Dive Rite ally backplate as it is easier to vary weight with it. When I use my 7/300's then I'd be too heavy with a steel plate and can't see the point in buying two backplates. With a v-weight and light cannister then I'm weighted perfectly for the sea with my 12's, no v-weight for the 7's. Good for travelling with as well.
Cheers,
Stuart
"I hate to advocate drugs, alcohol, violence or insanity to anyone, but they've always worked for me" Hunter S Thompson