I have done this a few times. When I first started I got advice from my sister, who at the time worked in Pomegranate and was able to obtain very professional advice. If they are making BIG BUCKS off drying salami, you can be sure that they are doing it right! Dried salami sells for triple the price of regular salami!
Anyway, here are a few suggested answers to your questions:
1 – the smell is only in the first few days, when the most moisture evaporates. After that, it slows down. To maintain the smell – and keep you in regular supply of dried salami (like if you want one every Shabbos,) you would have to hang up a new one every week. You can divide the two you buy (if you are buying two at a time,) and keep one in the refrigerator for a week before hanging it up. You just have to remember which ones are from when, to know which one is ready.
2 – You might want to not hang them over anything important, like carpeting. Sometimes they drip a little – again, mostly only at first. Or just leave a rag on the floor directly underneath. It is at most only a few drips.
3 – There is no absolute time. It depends on how dry and hot the air is. They typically take around 4 weeks. They are edible at any time. If you like them less hard and dry, eat them after two weeks (sometimes my kids just couldn’t wait any longer than 2 weeks!) I think mine were ideal after 3-4 weeks, and too hard (for me) at 6 weeks. But that might be perfect if you are cutting them thin and small for recipes, like tiny chunks on a salad.
4 – Be warned, that sometimes they just don’t make it. There is always a risk that it could become rotten, moldy, or buggy. No big deal, don’t give up. Just throw it out and try again. If it happens more than rarely, the environment they are hanging in is not ideal – too moist or hot or whatever. Move them elsewhere. When you first hang them up, wipe them off well to remove the external fat and moisture that will spoil faster.
I hang mine in my basement, while my aunt hangs hers in her kitchen. She lives alone, whereas my kitchen is often cooking for a large family and is probably too hot for it.
B’teavon!