Depends on how firm you like them
. I just picked a couple off our Beefsteak tomatoes (not a patio variety, but rather an indeterminate plant) and they were just right. No green to be seen, but hadn't progressed to mushy by a long shot. Generally speaking, the flavor is not at its peak if there's any green yet showing on the maters. With patio tomatoes you're probably going to have them ALL (bush type plant) getting ripe at about the same time. You'll be able to see which ones are at the peak of ripeness in no time at all!