I am looking at the Exmark TTHP 36 and the 48 and also the Hustler Trimstar in both of the same deck sizes. Is 17hp enough power for a 48" and is 15hp enough for 36" with two blades? I am really having a hard time deciding on which size I should go with 36 or 48. I am using a 42" Craftsman right now, do you think a 36" would be more productive than the 42 I am currently using? I know the quality of cut is going to be better but what about finishing faster? Sorry for so many questions.