Great point!
As Jabarabu is pointing out, if you are a DSX player, downstroke string changes are your thing. You shouldn’t really have to worry about upstroke string changes since they don’t work with a straight DSX joint motion. The winning move is not to play. Just ask John McLaughlin!
However: if what you are asking about are things like the Paul Gilbert lick, then what you are really asking about is mixing both escapes. There are precisely two ways to do this: double escape motion, or two-way pickslanting. Both methods are known, and we have solid ways of teaching both.
So I highly recommend @tommo’s suggestion of doing a TC. We’ll check out your core motion first to make sure it’s what you think it is, and make any improvements there that we can think of. Then we’ll make sure that single escape lines are working perfectly when needed, as well as hand sync even on a single string. Then if you want to do mixed escape stuff, we’ll make sure your form is compatible with either DBX or 2wps and get one or both working on some basic phrases. That’s the roadmap!
Honestly, this is a four-note lick and should not be a thing that people spend years trying to learn. I don’t mean to trivialize the difficulty of learning picking technique. We’ve seen every kind of problem at this point and we know how sticky mechanical issues can be. On top of this, none of this stuff was obvious when I started.
I just mean that I hate to see people beat their heads against the wall when we have better information now. Again, the two approaches for doing this are known, and we have good methods for teaching them – for many different underlying joint motions / picking styles. So if we can help, we’re happy to do it.
Finally, as a general comment: I think the Paul Gilbert lick is a musical empty calorie that too many people have spent too many years working on. The typical end result of learning it is… that you can do the Paul Gilbert lick. It tends to make everyone sound exactly the same. I’m not knocking the usefulness of the underlying mechanical skill. But the lick itself, played in the classic way, has a musically homogenizing effect. Aside from the simple fact that people like doing things they can’t currently do (and I get it), it hardly seems worth all the effort that has been spent on it over the years.