I don't like the under the muscle thing.
I think it was developed for women who have had to have complete mastectomies and there isn't really any breast to work with.
I know of quite a few FBBers that have had under the muscle taken out and redone.
One swears she has flattened hers out. Another pro I know ended up with one of hers under her armpit due to still training chest.
When you are dieted down, you will have veins all over your chest as well, as muscle is more vascular than the connective tissue, fat and skin.
Ask your plastic surgeon about a partial sub-muscular. They put the implant under the muscle fascia along the center and top of the implant to hide the edges, and it doesn't affect the muscle at all.
Can you still get silicon implants in Canada?
Liquid silicon gel is still the most 'breast-like' material IMHO.
They are still squishy and jiggly, but with a bit of firmness (unlike saline) then.