Like Joe, I'm not familiar with Nelsonite. If it's something like PEG I don't care for it at all. PEG is essentially a plastic resin which displaces water in the wood, if I understand correctly its process. The water is replaced by plastic and that's what it looks like - plastic. Ugly. Ugly. Ugly. To my eye, anyway.
I turn practically everything I do from green, wet wood. I turn from a rough log to finished size, shape and wall thickness in one session. I turn bowls (both "normal" and natural edge, end grain and face grain), hollow form veassels, and other "artsy" shapes. I understand and expect, welcome actually, the fact that as these pieces dry they will warp, somethimes a whole lot and, yes, sometimes they'll crack. However, I'ver go my "crack" rate down to around 1 to 2 percent.
Before I get to my "rules" for avoiding cracks, let me pass on a little of my understandig about green wood. There are two kinds of water in the wood - free water and bound water. Free water is the water that sprays you as you are roughing and turning the outside of a face grain bowl. It's like the water you can squeeze out of a saturated sponge. It's not our cracking culprit.
Bound water is. This is the water held in cell cavities like water in a glass or bottle or, in the case of wood, in straws - wood cells. As wood cells dry out, lose water, they shrink. Since heartwood is a fair bit more dense than sapwood, it'll release it's bound water more slowly and shrink less.
Our problem then, is to slow down the drying rate of the wood to allow the sapwood to dry at more or less the same rate as the heartwood.
Finally, bottow line. Here's what I do. Rules: (no such thing as a hard-and-fast):
Absolutely no pith allowed in the bowl, no cracks in rim, etc.
Turn to final shape and dimension. Sand to final grit. (I go to 600, generally) At this point I saturate it with my finish of choice Watco Danish Oil.
Thick or thin, wall thickness must be uniform from rim, down the sides and across the base. I've turned bowls from 1/8"- to 1"+ thickness from gnarly woods without cracks. Consistent.
With, especially, thicker forms (bowls) I then put it in a paper grocery bag with three or four handsfull of its own shavings and put another bag over the end to close it. Let sit for 2 or 3 weeks or more. If it's OK then, I dump the shavings and put it in fresh bags for another couple weeks. If everything's still alright (most likely) proceed with watever additional finishing you're contemplating. If not, recite some of those words Matt Wimpee claims you need to pay the preacher for and go on to the next one. It'll be better than this one could ever have been, anyway.
"Get it right, you're a star. Get it half-right, you're a gas giant."