i would not be worried about his handling, there are lots of d2 teams with cs with wondrous rebounding but atrocious handling and they get a ton of rebounds - yeah they do have a few turnovers but nothing crazy
in fact i have a guy myself who is wondrous/pitiful and he gets a lot of rebounds
and as for your best in d4 being prominent - seems great - i was never in d4 but i think my best rebounder was probably about that when i won d3