Straights and auto-pilot.
I am a three-month newbie with straights after 50 years with DE razors.
When I shave with a square/spike point, I have to know where that spike is or I am in serious trouble. The point of a Case Red Imp 132 left me with a three-inch vertical slash in front of both my left and right ears on my very first shave with a straight. I learned really quickly to keep aware of the point.
After a year or two I might be able to really answer your question about muscle memory. Right now my memory is focused on those two first slashes.:)