So in prep for using the alternate aft piece, I made a bulkhead from two pieces of (I think) 0.20 styrene sheet, sanded to match the hull contours. The gap at the top is for wires. I put this in because even with this setup getting this all together when I close up the hull will be tricky, and there is a chance for the alternate part to slide further back into the hull. This will prevent that.[ATTACH=full]88229[/ATTACH]And here is the bulkhead with the alternate puece to show how this will work.[ATTACH=full]88230[/ATTACH]