Since no one else is going to answers, I guess it's up to me.
I've got all four compartments. The excess (flash) that needs sanded is pretty obvious. If you're not sure, DON'T.
The big this is "test fit", before you glue.
When you first lay the parts out, they may not appear to match up. But they will.
With the hull side and deck held between the two bulkheads everything should stay in place. If there's any flash, it'll be obvious.
The only flash, I remember, is on the end of the deck and hull side.
The hardest part on, any of the kits, are the push rods on the engine (small pieces of cut wire), in the Engine Compartment kit.
Lastly.If you plan to use the YMW Hull Tops, you'll have to sand the bulkhead edges flush with the top of the compartment. AND, sand/grind a truck load of resin from the inside of the hull tops. For the torpedo room, you'll need to, CAREFULLY, cut away the torpedo loading trunk from the hull top, so the loading trunk on the compartment can stick through.
Fitting the hull tops is tedious and time consuming, but IMHO, well worth it.
I'm still waiting for the "Forward Battery/Officer Quarters" and the "Motor/Torpedo Room" kits.
If you have any other questions, let me know. These are pretty straight forward kits and should present few problems.
Mike K.