I've spoken to Dave Kreisel who supplied the beading. He advises warming it first especially at the corners. Fixing it in place with tape and/or staples but fitting slightly "in" so that the beading slopes downward slightly. Then when the wing is offered up it makes a really tight fit against the bodywork. Also at the end cut longer and then cut the core back so as you have enough of the covering to wrap around the end to make a neat end and the core is covered. If you have the standard black moulded beading this is not relevant, only for a covered core
K.
I'm sure the beading is there just to cover up any gaps between panels so if you have no rear valence there's no point. The ally rear panel is folded around the wooden crossmember so is still a water trap whether there is a valence there or not. I'll make sure there's lots of sealer squirted in that area. Thanks for pointing that out.
I've not come across ACF50 before. I could ask whats so special about it but it sounds like this post could get long! I'll look it up.