Coll is lovely, but I only ever went there by ferry via Tobermory. Many times, always at Easter when the wx was perfect, and it was!
My claim-to-fame is that I discovered the oldest neolithic pottery on the island, during a croft "dig". Not substantiated by the British Museum or anything, but it was a find indeed. Boring, I know.
A pal of mine landed there upon the return of the Piper fly-out to
Barra & Tiree (they were in a Horster, and diverted to Coll) before the latest improvements, and I understand they were well looked after.
So in essence, I can't answer your question at all.
Sounds like you need to go and try it out, eh?
DT