I can't say anything about the gelding them younger with make them taller because we don't know how tall they would have been otherwise. I can say that the longer you wait to geld him, the more likely he is to develop the "stud" appearance; the cresty neck and large jaw typical to draft stallions. My Perch John was gelded at 4 and still has a couple of studly attitudes (though he is getting better). I plan to get my cross gelded no later than 1 year old. I could geld him now if I wanted because he has already dropped but I want him to have a little hint more muscle.