Hi JB,
Cool, I say go for it!
A couple disclaimers: (1) there are many other people here who could give you better advice than me, I just started turning in May, and (2) the answer is probably a matter of taste. That said:
-- I like 2 to 3 turns. The first (non-total-crap) kitless I made was a rollerball, which I still use, but requires about about 7 turns of the cap. It gets on my nerves, but I keep it for sentimental reasons, and it's the only kitless pen I own.
-- I just checked my garage and I'm using a 1/2-24 taper tap and a corresponding die from the Machine Shop Discount Supply; I can't seem to find my receipt, but it wasn't too pricey. I don't think this is the optimal tap/die set to use. If you use a triple lead tap/die set, then you can have larger threaded areas without the excessive number of turns, but that equipment is a little pricier. If you're interested, check out A Turner's Warehouse to see pricing.
I don't want to derail this thread too much more. But some quick things:
-- I suggest looking at RJBWoodTurner's videos on turning the body of a kitless pen (and he does the section and cap too). Great intro to making a kitless, I think. Also, a tonne of helpful info is available on this site, mostly concentrated in the library and in the advanced pen-making section.
-- I'd treat your first few kitless efforts as experiments. You'll likely make mistakes or sub-optimal choices, and learn from them. Also, take a look at what the pros are doing, people who have been doing this for awhile, including (but exhaustively) posters like Teodor, jalbert, wizard, and a bunch of others, and Renee at Scriptorium Pens has a lot of images of her work which is terrific.
-- Don't worry too much about the threading; it's intimidating, but probably not the hardest part of kitless. Order of operations matters a lot more, I find. It seems there are many ways to make a good pen, and you'll settle on your own method (which itself may change) after awhile.
Feel free to message me on this site if you want to chat more.