Gio,
If you are on a budget then just use the Nova as you got it, 28 inch barrels and all!. Put the I/C choke in and stoke the magazine with 00.
I suggested to buy another Nova because I am a big believer in the Ghost Ring sights and the Nova Tactical sells for about $300 locally. Obviously, the Ghost Ring sights would be impractical on a gun that you were switching out barrels on. Take the gun to the range and get in some practice with the 00 and you will be fine.