I got beaten out of the gauntlet somewhere just past trig. In my current career of NDT, some vague, fuzzy recollection of plane geometry has helped, as well as knowing about curves and what inputs will affect them.
Like you guys' experience, the math is generally not needed on the practical application side.
As far as the kits, yes it would be great to be able to positively and truthfully answer the interview questions, but being able to document those experiences would be even better.
So far the HAM exam (I need another expensive hobby anyway) looks great, but I'm still going to exercise some more google-fu and try and settle on an online course with some practical exercises.