Hey @PickingApprentice, sorry for the delay! I’ve been thinking a bit about this type of issue - let’s say “speed above which your nervous system struggles”. From my experience with this solo, I don’t think this can be solved by playing at a slower tempo.
Probably a good idea is to take another lick that is about the same duration but a bit easier for the picking hand (say - using only your favourite pickslant/escape path -possibly covering all 6 strings along the way). Or, simply add some legato “cheats” here and there in the 5s lick itself (like I did), to make it fit better your current technique.
Then, try to play this simplified lick at, or a bit above, the speed of the “5s lick”.
The idea is to remove all other obstacles (difficult string changes and so on) and get used to the feeling of that speed.
Once you have experienced that speed, you can try to go back to the original task and add the additional complications.
Disclaimer: just my ideas, no real science here