Last night I worked out how to turn my UWPS RDT Wrist DSX into a version with a Zero Degree Pickslant!
With a Zero Degree Pickslant should you be able to do both a RDT DSX wrist motion and a deviation based USX motion from this one position? I think I can do that now but I just wanted to make sure that was the goal before trying to apply this to my work on DBX 
I think USX needs a downward pickslant, so you may need to supinate a little more to achieve that. I’m not 100% certain about this though, but I could have sworn I read this on a post recently…
Yeah that’s what I thought which is confusing me a little!
Maybe it’s that a Zero Degree Pickslant is capable of constant DSX and the occasional USX?
So with this position maybe I shouldn’t worry about being able to do a perfect deviation based USX but close enough that it will work occasionally or with very minuscule adjustment? Will be interesting to hear what more people say 
I think it doesn’t do continuous USX due to garage spikes , but can do occasional upstroke string changes in this form. You may be able to alter your form slightly for USX phrases though, but I’m unsure about that.
My understanding, which is often close yet flawed, is that zero degree pickslant RDT gives you DBX. I think from the same posture you can get DSX but I can’t remember if that requires just a little tilt towards an upward slant. Experiment and see what happens! You’re a pro at learning new motions 
Okay my next question would then be what does someone like Andy Wood do when he goes into high speed DSX mode, does he lean a little into the the upward slant? Or can he do it all with zero slant because obviously he’s still getting the occasional DBX escape?
I thought I was pretty good at using the occasional helper motion for my upward slant but even after a little experimenting with a zero slant it starts to feel a lot more automatic
As far as I can see, he does not slant the pick, but his dsx motion and dbx motion are not the same. You can see he does rest strokes on the upstroke at higher speed, so upstrokes don’t escape.
The zero degree slant is more of a general setup. The wrist motion will determine whether it’s dsx or dbx, not the setup as such.
One interesting thing I remember is in one of the interviews where Troy has Andy play as fast as he can. It’s in the neighborhood of 6’s at 140 bpm. And it’s the Gilbert 6’s too, so it’s DSX friendly. He swipes in it, a lot. Why this happens I’m not sure. His elbow starts to get involved but that pattern should be just fine for even some one who uses only the elbow (and I think here his wrist still primarily drives the motion). Something about that trajectory really flattens out when he floors it. This is all an observation and by no means a criticism of his awesome playing. I only noticed the swipes because I could see them.
I am tempted to write a lot of words but… cough cough… video… cough cough 
PS: you are a great player and already had experimental success with your killer forearm motion, So I’d just say apply the same experimental procedures to this new setup and the phrases you want to play with it. The ultimate test is just whether it works or not
I believe my main form to be exactly that, RDT DSX with basically a zero degree slant of the pick, and I definitely cannot do continuous USX, I can however do it as a helper motion from my wrist, but I try to avoid it or minimize it when playing fast, since it takes away from my speed noticeably, it’s still fast so it’s usable for me as a helper, but not nearly as fast as pure DSX, or like the guys that can do DBX or secondary motion at will reliably like MAB or Kiko Loureiro. But if my memory serves me well zero degree pickslant should allow for DBX.
I’ve noticed a lot of guys do it Gilbert, Tremonti, despite being DSX main, but their pickslant looks neutral.
But Mike Stern from the looks of it has a slight downward pickslant. So I guess for continuous USX you do need it even a little bit.
I believe Andy is capable of secondary motion using only wrist and also forearm like MAB, so he has 2 options there. And I believe also Troy mentions when going into real high speed like on tremolo it’s only DSX for Andy.