is submitting same site to same tgp bad
 

What i mean is, is it smart submitting the same affiliate site (with different content) on one tgp if you still get a good rate. Or does each tgp get 80% of returns visitors and they will only signup for your sponsor once and in a couple of months ill start converting poorly.

If you only use each sponsor for one gallery you will very quickly run out of sponsors. You should however change it up as much as possibly without hurting your conversions. Use different promo material for the sites your promoting etc.