I'm in two minds (as usual

).
The crop was good - I have a lot of tobacco leaves. I have LOADS of tobacco leaves. And I was right about the colour curing - the leaves which dry the darkest brown do have the most nicotine, and the leaves which dry almost yellow have virtually no nicotine. The received wisdom is to mix the two, BUT, BUT, BUT, even the darkest brown leaves, I feel, have only the nicotine content of standard shop-bought tobacco. Mixing would produce something along the lines of extra-mild tobacco - something which leaves me a quivering wreck.
I'm hoping that other received advice - specifically that tobacco accustoms itself to local conditions and next year's crop will be better than this year's crop - is true, given that I got only two or three leaves per plant which attained the darkest brown colour-cure.
The other thing I gathered was that the "good" leaves are those which take on an "alligator-skin" appearance. Not being used to alligators in my ponds, I wasn't sure about this. But it appears to be true too. The "good" leaves were, in fact, the ones which had developed a rumpled and bubbly appearance (that's the best description I can give).
The other thing I've noticed is that the taste of dried but otherwise uncured tobacco (i.e. not fermented in a kiln) is not unpleasant. It's very different, but I quickly got used to that given that the "bite" on the throat was definitely there.
All in all, it was a worthwhile experiment out of which I got probably a couple of month's worth of usable tobacco. OK for a first attempt and certainly worth continuing next year.
So ...
Transplant your seedlings early. They look so fragile at only 1/4 of an inch high, but they're tough buggers and suffer no harm. They may take a bit of a check at this stage, but it's nothing like the check they'll take if you try it later.
Get them hardened off ASAP - you need as much growing time as possible - and plant out after any threat of frost has gone.
When they're established, water them well - then water them again. They LOVE water. Oh - and get some stakes in the plot if you live in a windy area. These plants grow - and grow - and grow.
Use a general-purpose fertiliser up until the point at which they try to flower - then stop. This, apparently, forces nicotine concentration. When they do start to form buds, pinch them off mercilessly. While you're at it, pinch off the side shoots which will begin to appear in much the same places you'd expect with tomatoes. Don't stop there, because they'll keep throwing buds, side shoots, and even suckers from the base of the plant. Get rid of them all - at regular intervals.
All the time you've been doing this, keep your eyes on the leaves and take out any which begin to show signs of yellowing (usually bottom to top). Continue to do this throughout the season. Hang up any such leaves - upside down - in a dry, airy place where they will happily dry.
Continue to harvest leaves until either there's a threat of frost or the plant begins to look tired, at which point uproot the entire plant, chop off the root, and hang the plant upside down in the same dry, airy place.
Check your hanging stock at regular intervals. Some leaves will colour cure completely to a shade of brown. Others will retain a bit of green. If that's the case, mist them lightly with a water spray. All green will, eventually, disappear.
That's it, unless you want to go into the realms of building a curing kiln (but I'm told that this process reduces nicotine content - I haven't done it). I have noticed that the leaves dry in accordance with nicotine content. The earliest leaves (very little nicotine) dry light yellow and very dry - you can crumble them in your hand. The later dark brown leaves (especially those harvested after potential flowering) retain a flexibility - you can open them out without them falling to bits.
That's just about all I've learned. Over and out.
Mike