Our pug is at a good weight for her at about 18 pounds. She is female and black colored. The girls run a little lighter weight than the males and blacks tend to be smaller than fawns. I have seen 30 pound fawns, but at that weight, they were super fat and appeared to have trouble walking. I try to keep our dogs at a good weight and gauge that by how they look and feel (stocky-wise). Eye problems are very common in the bulgy eye breeds and I have had some luck with putting cod liver oil drops into the eyes, but that stinks like the devil. You could try vit. E drops, too.
As to diet, I have been feeding homemade for many years. I use Pitcairn's Natural Health for Dogs and Cats book for my recipes. The easiest recipe I have stuck with is a cooked oat/meat/veg with added powder containing brewers yeast, lethicin, kelp and vitamin c and e. Since you already feed homemade, you probably cook in mass quantities like I do.
We were given a 3 year old Frenchie last year and the difference in her coat and health is amazing after 9 months. She had been on a kibble for sensitive stomach made from salmon. Yech, just the smell of that junk...long post, I know, but this works for me. Good luck and how nice of you to take in this dog.