Doug,   You are asking the techs to give you information they use to make a
living.  In most cases they will not be happy to do this, particularly if
you slow them down by asking a lot of questions -- further impacting their
income.  If you find a really super older guy(1)  and make arrangements in
advance for some lessons, and compensate him for this, you may have an
agreeable experience.  Otherwise, be prepared to be treated in a brusque if
not impolite manner.

(1) Age is not an absolute requirement, but I'd try to choose someone well
experienced in the subject and be totally up-front about your needs.  Also
be prepared to arrive when the tech wants to work on your project..... etc.