I've read Danthurs write-up a few times, and seen similar posts on other forums. I have the spacers and know where to put each one, 3 of 1/4" ID x 3/4" long and 1 of 1/4" ID and 1/2" long. So, my question is, how does spacer length affect shift firmness? I would prefer softer "buttery" shifts, what is the best combo of spacer size to get it?

Yes..spacer length does.

If you reduce the spacer length you will get softer shifts. What the spacer does is limit how far the accumulator piece moves.

I think it works like this:
As it begins to fill the clutches of the gear start to engage. When it fills up or the spacer limits it and it fills, then pressure is directy held on the clutches.

Makes sense, shorter spacers = more like stock (no spacers), so softer shift.

Is there a minimum length for the spacers to be effective? 3/4" for the bottom spacers seems to be recommended everywhere I read, what happens if it'* only 5/8" or 1/2"? Same for the top spacers, is there a minimum effective length? I guess we'd need to know how far the piston travels in stock condition. Anyone have that obscure tidbit handy?

My main goal here is to keep the dang thing from going into the max adapt mode, it'* happening more often lately, and the jerky thunking shifts and tranny whine irritate the crap out of me when it happens.

The setup I have in my writeup is a medium shift. You will hardly notice it under normal driving. Less spacer will make little difference from stock.

Good deal, I'll leave the spacers as you have them. Got that and the gas gauge fix to do this weekend. Maybe do the oil pressure sender, too, since it'* been sitting on the toolbox for a year now.

Thanks, guys.

Well, it was remarkably uneventful. Everything looked great when I pulled it out, spacers went in, put it all back together. Seems to work quite well, I like it. The single longest phase was removing and putting back all the damn bolts! Dan and Bill, thanks again! You two, and this site as a whole, have saved me a ton of money.

The gas gauge fix is another story. I started it, but am having difficulty getting the metal plate to turn so I can pull out the sending unit. After beating it for a while, I set everything down and watched football the rest of the day. Getting some help tomorrow, should be good after that. Getting tired of guessing how much gas I have.

Glad to hear the shift kit went in easy. And happy the write up worked out for you. Always nice to go fast, not broke.