How much wet?

I'm switching Mollie over to an all wet diet - so far the addition of wet has been amazing. She has had GI issues, and since she started eating wet she's had no issues (no loose stools or vomiting - yay!). I do have a few questions though
1- How much wet should a 10lb. female cat eat? I've been buying the 3oz. cans (Pro-Plan and Pro-Plan Select), dividing them into thirds and feeding her 1/3 morning and 1/3 evening - followed by 1/4 cup dry Nutro Natural Choice at night. We are almost out of the dry, and once she goes all wet, how much should I increase it to? If I read the back of the can right, she would be eating about three 3oz cans a day and I just can't imagine that (she never begs for food and never seems hungry - although she does get excited when the wet comes out ).
2- What is a solid wet to add into her diet for a rotation.
3- Why are so many people opposed to by-products? Don't cats in the wild consume most of their prey (i.e., eat the stuff that we think is yucky)?
As always, thank you SO much for all of your help and knowledge!!!!!

Thank you all!
Sharky - Here are the two wet foods that she is eating now; can you look and tell me if they are good or not.

1- Pro Plan Selects Turkey & Wild Rice : Turkey, poultry broth, liver, fish, wild rice, oat meal, egg product, guar gum, spinach, sweet potatoes, blueberry pomace, potassium chloride, choline chloride, taurine, salt, carrageenan, zinc sulfate, Vitamin E supplement, calcium phosphate, thiamine mononitrate, ferrous sulfate, manganese sulfate, Vitamin A supplement, copper sulfate, pyridoxine hydrochloride, niacin, Vitamin B-12 supplement, riboflavin supplement, calcium pantothenate, menadione sodium bisulfite complex (source of Vitamin K activity), Vitamin D-3 supplement, folic acid, potassium iodide, biotin.

2- Pro Plan Chicken and Liver : Water sufficient for processing, chicken, liver, meat by-products, poultry giblets, artificial and natural flavors, tricalcium phosphate, guar gum, potassium chloride, taurine, salt, Vitamin E supplement, zinc sulfate, calcium phosphate, thiamine mononitrate, ferrous sulfate, manganese sulfate, Vitamin A supplement, copper sulfate, pyridoxine hydrochloride, niacin, Vitamin B-12 supplement, riboflavin supplement, calcium pantothenate, menadione sodium bisulfite complex (source of Vitamin K activity), Vitamin D-3 supplement, folic acid, potassium iodide, biotin.

Any recommendations to begin adding in to a rotation?
Thanks again!