I doubt the OP was planning to
train in the 421

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.

I should also state that I have about 15 hrs of instrument instruction already
in a c172.

The traditional route of getting instrument then commercial in a single then
getting multi would be less expensive initially, but considering that i need
about 250 hrs of multi time to be insurable in the 421 I would then have to
build multi time somehow and that won't be cheap.

It just seems that doing all the training in the multi makes more sense. Plus
it is intensive training, 3-5 hrs every day, so the learning curve should be
quicker. I understand the point that I want to get the basics down so I don't
fall behind.