<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">3. Important. I would not hang it unless I knew temps would be lower than 60 the entire time. Humidity should neither be too low nor too high.
4. It should be 70% of its starting weight, weighed just before hanging. You can, however, go longer or shorter and not worry about the weight. </div></BLOCKQUOTE>
I've been doing ok with things like jowls, belly, pork tenderloins, and duck breasts in 55* 50% RH. They don't have much of a cross section so there isn't as much worry about case hardening.
Adding a mold is supposed to help slow drying and can help when conditions aren't ideal. Its something you should consider investigating. The mold will also prevent nastier stuff from growing on you meat, which is an added benefit.
70% is ideal for meats that are intended to be eaten as is. With guanciale, you'll most likely be cooking it, so really, you're looking to "mature" the jowl, deepening its flavor and bringing out some musky/funky flavors. You can tell a lot by squeezing the meat, you don't want it to be hard, nor do you want it to be really soft.
Keep in mind, that it will have to be kept frozen if not dried to 70%.