I do something similar, except instead of consciously visualizing the string I want to pick, I try to be aware of how my hand feels against the strings, my hand position relative to my pinky (when using the pinky as an anchor), the angle I hold my hand when picking, etc. Once I internalize the sensations of moving my pick from one string to another, my accuracy improves greatly.
I first do this slowly while looking at my hand (to make sure my form is exactly how I want it), then try to repeat it without looking. I can actually start to detect my knuckles passing over the strings and the strings touching my curled-under fingers when I’m right-hand muting and feel the distance and angle between my pinky and my thumb/index finger when using an anchor-finger.
I deliberately practice this while looking at my hand until I can reliably pick the pattern I desire to a 60 bpm metronome, then start purposely closing my eyes for awhile, occasionally looking down at my hand to re-calibrate, then eventually do it at 60 bpm without looking, then start to increase the speed until I get it to where I want it.