I'm not so sure Sins is the right platform for a Gundam mod.
In Gundam the focus has always been on the mobile suits, and those would be so small that you'd only see their symbol or a dot with an engine trail most of the time.
And there are just so few of the bigger ships. The Salaris, the White Base and one more ship which I forgot the name of for the Earth side and that one battleship and one support ship for Zeon and that's it.
Not enough to fill up frigate, cruiser and Capital ship slots.