Looks too small to me, unless it had a large span.
The tailplane span does not look unusually large in any pictures, although your reasoning may be sound and may have some relevence to another feature of this aircraft
and that wheel is bugging me - can't fathom if it's a partially-retracting nosewheel or what.
It is the nosewheel.
was it designed to be quick, because it certainly looks it.
Mmm, well it was not designed as a racer, but it is quick and has won speed (over set distance) records in its weight class which still stand today.