Chris: IMO Noman's is perfect for a beginner, can be done quickly and easily with equipment and chems readily available for anyone and has no significantly tricky stages. I think SWIM will move to Vovin's tek eventually but only when he has a bigger place and has subtly built up his store of proper equipment.
Stick to Mimosa. Most quotes of volumes etc etc are for Mimosa and generally speaking the quality of what you get is good. If you're in the UK I can suggest a tried and tested supplier. For the states there are innumerable sources.
IMO, extracting the spice is the easy bit, the hardest part of this whole thing is learning to smoke it and getting enough to get the full effects.
Things to note: you'll prob come across this anyway in your research and no doubt you'll be asking a few more q's along the way but be aware that the ammonia wash in the published version of Noman's tek is no longer generally used. SWIM has extracted pure spice very happily by leaving this out and using a soda wash. Also, IMO don't buy prepowdered bark; it's not 'that' hard to powder it yourself, and prepowdered uses different quantities of water (and IMO is more liable to be less good; just my personal exp/opinion).
Bite the bullet and you could have spice within a week!
"Language is a cracked kettle on which we beat out tunes for bears to dance to, while all the time we long to move the stars to pity." - Flaubert
I do not engage in or condone illegal activities. Most of what I write is on behalf of people I've bumped into, usually several years ago and in countries where the things I mention are legal.