Badwolf: MC120 doesn't exist, if anything it could be the mediator, but I have plans for that
Victories are heavy missile cruisers, they don't have big bays a shuttle and 3 fighter squads, the Imperator carries 24 walker barges and a prefab garrision.
Praetor is bigger than an ISD, smaller than a Mandator (which is what you are thinking of) of course the only canon information is that the Mandator is a star dreadnaught and can take on 1000 recusant destroyers (4-5 per venator and 3-5 venators per isd so it is worth 40-80 ISDs , and the Ex is worth about 76-150 ISds by pure calculations,)
the Republic vessels I can't find anything that would have a lot of strike craft, this is balanced by the fact that the Venator is very cheap and has lots of fighters.
The strike craft numbers aren't final, but there is also the quality of the strike craft. Alliance > Republic > EMpire > CIS effectively with a few special exceptions.