As an MSR leader of long years, the most useful toon is a */Forcefield/* toon of any AT.
You can anchor the raid and protect it.
You can do damage, buff, debuff, heal, whatever.
As for "best toon" for a ship raid?
As always, the answer is, invariably, what's FUN for you?
I'd rather have 20 people who're having FUN at the raid than 48 people who are miserable or just going through the motions.