I have the exact same issues with my M/T DRs: either I hook really good, if track prep is decent and the track is still pretty clean, or I can't hook up at all and just spin at and/or off the line.
They used to hook up just great, but upgrading to a 3K stall converter just killed traction, or the track is not being prepped like it was before.
When it was hooking up, I was running the rear dspecs at 5-5.5 turns out from full, so running them a little soft, but it's what worked at the time. And that was with the DR tire pressures around 25, and launching at only 1200-1500 rpms and flooring it at the light.
But now I realize, part of my traction issues is likely due to the setup; as mentioned, having the shocks set so soft, the tires can't be getting planted hard enough, so they'll spin at or just off the line now. Trying lower tire pressures, down to about 18, didnt help.
I haven't tried lowering the tire pressure more while firming up the rear dspecs, but I suspect it would help to put more downward pressure on the DRs at launch with firmer shocks, which should help at the line. But, losing traction off the line and through 1st gear, that's no good; too dangerous. I don't like to get out of the throttle when she breaks loose, and only get out of it very rarely; usually i can get it straight and going, but that plays havoc on consistency of course.
Next time out though I'm going with M/T ET slicks. If it means reducing spinning anywhere at or off the line, it should be worth it. I'll be trying near full hard (1-2 turns out from full) on the rears, and full soft up front as usual.
