I had a hds9 on the bow of my puma. No access hole under the trolling motor pedal. The cup holder up there is just silicone sealed down. I peeled mine up and reached across. It was a chore! Made the gf help! I will add, I contacted balzout directly and they sent me a base, that was the same as the old lowrance unit. So I didnt have to drill new holes to use the round base they normally come from. I would go with a shorter arm as well on the 12″ unit up there. I’ve heard of one or two of the really long arm ones having issues on the big units/ great lakes area.