Bolt supply houses are going to have better quality fasteners than a Lowes or Home Depot, so c keep thatin mind. If you need to cut bolts to length putting a couple nuts on the bolt is helpful in not having a thread reverse, then just a few strokes of the file to taper that ending and clean up the cut end.
Putting a bolt too long in some holes can crack cases or do other damage, or prevent it from being.torqued properly when it bottoms out.
Nice part of some of the better stainless bolt kits is they sub-package the kit for various areas and that's super helpful.
David