The Grumman TBF/TBM seems to be a pretty big plane at 54 feet wingspan
and 40 foot length.
The SB2C is only 50 feet by 37. I haven't looked at all World War 2
carrier planes,
but the TBF is bigger than the F6F (and thus F4F by default) Heck,
even the F4U is
only 41 x 33.5 feet.

Was the name "Beast" in reference to horsepower or flying
characteristics?

That, brings up another question: what was the largest planes used on
WW2 carriers?
(Not counting B-25 for Mitchels Raid)