the Interdictor's hangar bay can hold 2 squads of TIEs and a couple of shuttles max.
the interdictor is a good 1000 meters shorter than the ISD, so I don't think a corvette would fit.
Oups, I was talking about the ISD model not the Interdictor >_<
About your screen, Have you modified the FOV ? Because when I was converting Warlords model with correct size for each ships, I had the impression that the ISD was still a little to tiny compare to the ISD in X Wing Alliance and Star Wars Battlefront 2.
Or perhaps, my X wing went too fast :/
I don't know if you had downloaded the Star Wars Warlords conversion for Freespace SCP ^^ and try some of those missions. If chief1983 has sent the link to the mods ^^.