Taking my Boss on a guided hunt and his VM has a capacity in the tube of (3) 2-3/4" and 3" shells, and only two 3-1/2" shells. We will be shooting 3-1/2", but I am worried if we get checked by a warden if this passes the test, since capacity with the shorter rounds is 3 in the tube?

All of my 3 1/2" guns will only hold two shells of any length in the tube.

The warden will use 2 3/4 inch shells to check gun capacity.

this

going to have to get by with two, 3.5" rounds

any thing you can drop with 3.5", you can drop with 3"