Cusco - if I read your question right, although I don't have experience of the Beech 18, in most aircraft at altitude it won't make much difference (slightly different stall speed due to altered W&B perhaps?) to handling.
T/O & particularly landing will be a whole different world though, which was kind of where my question was going....
The T/W version of the Beech 18 has an incredibly high tail position on approach, although flattens out on short finals. Anyone know why this is?
(Just google "Beech 18" & you'll see what I mean).