I don't want to tell you how to build your plane, so please don't take this the wrong way. A shoulder belt out of an old van will prevent you from eating the instrument panel, but it will also burse your chest and bend your tubing every place you have it hooked to. this I know for a fact. I think your gear cluster is the strongest point for your lap belt. Also should you find yourself upside down and gasoline is dripping all around you, you won't like your seat belt release you have. I have seen them stick and almost impossible to get open. Plan to take a sharp knife with you to cut the seatbelt if you use an auto type release. I had a set up very similar to yours when I lost an engine and made a rough landing. Leonard's aluminum seat is very, very strong, actually stronger than the fuselage. You would not be disappointed with it. .
