I've read much about wingtip installation. I'm using a popular method of installing piano hinge instead of screws to hold the wingtips. Lots of work, but removing the wingtips for future maintenance is only pulling the two pins, rather than hundereds of screws. Also, nice clean look. The tips are pretty flimsy and don't hold shape well. This improves after installation. You must watch the trailing edge in relation to the aileron to match. Making a foam "rib" helps hold the wingtip's shape while in process.