If you have not yet found this website theres a treasure trove of information about Leica screw mount cameras on this page.
I love my IIIa (1936) and wouldn't hesitate to use it anytime. It's small, light, nearly invisible and silent and judiciously applied sunny f16 works as well as most in camera meters. Theres some user tips in this particular link that I've always followed and have never had a problem in the 6 or so years since I found it.
Have a great time and send us some photos!