Before I got Mr. Belvedere I free fed my other cat, giving her a 1/2 cup of dry a day (she's on prescription for a UTI). However, now that I brought Mr. Belvedere home he won't stop eating! So Penelope has to have meals and what she doesn't eat I must pick up, same with the dog's kibble because he will find a way to chow it all down.
Currently I'm giving Mr. Belvedere a 1/4 cup of dry twice a day (i'm switching him from Purina that the shelter had him on to Royal Canin Persian 30) plus an 1/8th of a can of wet food with every meal. However, he is still trying to eat whenever he can. The vet advised me to watch him weight, he's already a little under 10 pounds (at a "good" weight).

Should I be feeding him more or do I ignore his meows?