Lots of guys gain well on a split routine like that where you train twice a day. Another perk is that it keeps the tissues opened up. Recovery time isnt that important when we're talking about your penis. As long as your erection strength is not suffering, and you are not totally draining yourself mentally/physically, do some more Penis Enlargement!
When I work with a hard gainer and myself for that matter I always push a split routine for girth. Girth is not so much about the type of exercise you are using but how much expansion it gives. I think doing two girth routine at different times of the day is beneficial because it puts the penis in an expanded position again.