I know it is slumming to buy Sears, but I already have two other C3 system items and those lithium batteries have survived very well on my occasional use regimen over the past 2.25 years. The right angle drill is a bit long but I think it will get the job done. I ruled out other battery systems. That Milwaukee was probably a better choice.

Looks like if I remove a large piece of inboard partition, I just might be able to slide pieces of rigid foam up the forward and aft sides, inboard, and bottom with a lot of patience, cutting, and glue. I sure would like to preserve air gaps next to any wood.