I’ve got some aluminum fascia to install and I’m curious as to the fastening methods used by everyone. I have done it once before and the way I was taught was to use a short (5/8”) soffit screw on underside/ the lip of the fascia (@ the hem) fastened into the metal of the soffit only. Is this a reasonable way of doing this? Is there a better practice? It seems like hitting wood/rough fascia with a longer screw/nail would have better holding power/wind resistance. What do you guys do? Is fastening metal to metal sufficient? Also.. with vinyl siding does anybody use undersill @ the top of a wall/ under a window? What about up a rake/ gable end? I plan on doing so but the last company I worked with felt it was unnecessary. Also does anybody fasten the bottom/hook of the last piece of vinyl with soffit screws?

thanks a lot! Sorry for the long post