Which leads me to a second question. Is there any reason to use a film of less than ISO/ASA 100 for contact printing? Based on my own experience I would say no, but perhaps someone has knowledge of a specific situation in which a very slow speed film gave better results?
WRT to your second question, I don't think so. In fact, I say I don't know of a reason to use a film with the speed of less than ISO/ASA of 400. I have photographed in the Big Bend NP and if anything the wind blows all year round. Having an extra stop or two can make a big difference. With contact printing there is no grain at all.