Trimmed both inlet diffuser sides and top for the 1” plenum overlap. Also trimmed the front of the left diffuser for a 1/4” gap to the aluminum inlet ring. Mixed up some epoxy flox to fill the holes in the sides and bottom of the inlet diffusers for redrilling after final positioning with inlet rings. Filled in some holes in the top of the plenum that were incorrectly drilled for nut plates. Used the leftover epoxy to fix a table knife.