I'm thinking about building a Omaha class light cruiser to IRCWCC rules. Problem is, I don't know how such a ship would work in Fast Gun since there are no torpedoes, and I also don't know if there are any problems with building such a small ship. Thanks!
You can build one if you wish, however it would be more difficult to build than a heavy Cruiser and of less use in battle. Normally we direct new comers to Battle Cruisers.
Omaha is pretty small and light. It’s been tried and did not work well. Start with a Houston class or a Von DerTan
You'd spend your offensive units on arming guns in the main battery. just the usual, weight distribution, instability, part size vs available hull size, increased costs for smaller parts, etc Small ships are too fiddly. Build a ww1 battlecruiser or an interwar heavy cruiser