I agree - I like my roasted necks, but the one that I have that isn't roasted is a Mighty Mite fretless (Warmoth doesn't do ebonol fingerboards), and I applied the same logic - even if I have to buy 3, it's not more than one really good neck costs. In this case, I won the lottery - neck "1 is straight after 5 years. I do think that your mental approach is a bit flawed, in that once you buy 3 or 4 necks (even cheap ones) one of them is bound to not twist (or twist so little that it plays just fine) - maybe you'll want to level the frets or something, but I'd guess you will eventually, assuming you take decent care of things, get a good neck.