I am the OP and no I don't plan on training in the 421 but rather in a
Seminole. I am leaning toward going to ATP or Ari - Ben for the
accelerated
school. In both programs you get your Multi first and then do all
subsequent
training in the Multi (instrument and commercial). When I graduate
from those
programs, I will have 175-200 hrs of multi time which will be
necessary for
insurance purposes in the 421. I do plan to fly a 421 in the future
and after
I get about 250 hrs of Multi time I can then go to FlightSafety for my
421
training to keep the insurance co happy.

That all sounds very sensible. You're right - nobody is going to
insure you in a 421 with 20 hours of multi time. I'm not sure you need
250, but you will certainly need 100 or more. I'm not familiar with
the Ari-Ben program, but quite a few people I know did ATP, including
some of my instructors. I've also taken a few checkrides with the
examiner who did the ATP rides locally. I know a reasonable amount
about the program, and it is much as you describe it.

You should realize that a huge chunk of that multi time you are going
to log will be safety pilot time - all your XC flying will be either as
safety pilot who also handles radios and maps or as hooded pilot who
only flies. The Seminoles are incredibly docile (think Arrrow with two
engines) and are equipped with dual 430's. In other words, don't be
concerned about being overloaded - that won't be your problem. Your
real problem will be the transition into the 421. I would recommend
that you get some experience in a rental C-310 first.

Michael