eno wrote:In general (unless you do bass string glissando on purpose) you need to eliminate the habit of "lazy" right hand sliding along the bass strings and instead develop a "jumping" movement where the fingers softly take off perpendicular to the board and fly slightly above the strings.
Good advice and close to the advice of a private teacher I had back in the day who studied with Able Carlavaro. I can pretty much minimize my squeaking using a somewhat similar method (hard to explain), but I can't get rid of the "creaking" you can get sometimes when you have a hard fingering that is using your three fingers and you have to move the fourth.
Villa Lobos' Prelude No 1 is great for this type of practicing. It's almost like you are lifting the pressure off the fretboard, keeping tactile touch still on the string and rapidly moving your whole hand to the next position then putting the pressure back down. I didn't have to purchase the polished strings (and I don't know if they were out there in the 90s).