When insuring our Aztec, we found very few underwriters (3 if I remember
right) willing to insure "transition twin pilots" i.e. transitioning into
a twin. Our lowest time/rated partner (the one the insurance is primarily
based on) had less than 500 hours, is PPL and IR. We all did our multi
training just before purchasing the Aztec, so we all had very low twin time.
Myself and one other partner are Commercial and IR, I'm a CFII and he's also
ASES. Only our PPL partner was required to fly 25 hours with an MEI before
solo in the Aztec. We were told (right or wrong) that our Commercial certs
and other ratings helped our cause. Our broker told us more underwriters
were interested and we got more quotes because of it.

Maybe he was just blowing smoke up our butt, but if it's true, then this is
what I would concentrate on:

Get your commercial certificate and build your time above 500 hours, then
get your multi rating. If you get your multi first and you save your money
for hours of twin flying, the hour building will slow dramatically. Your
best investment will be to build your time in a single, it will save you
some serious insurance premium bucks when you move into the Baron.

YMMV
Jim