Well I tried to carve on that expanding foam spray and I quickley admited defeat! That stuff has too many cavities, it's like trying to carve a marshmellow into a functional airplane part. I know guys have used this with success, but not me. Next try will be modeling clay.
I switched gear to the empennage fairing for the remainder of the session and did some intial trimming and fitment. I looks like it'll fit ok with minimal work.
Defeated by the blob! I obviously used too much, but either way I quit!