Good technical exercises to work on L-R hand Coordination

[NSJ]

Addressing technical weaknesses in dealing with the instrument--forget about music, for a minute.

What are some good exercises you have designed to work on specific technical problems you may have, particularly with left-right and coordination?

I have found that fingers 3 and 4 of the left hand are relatively weak in their ability to work together, so I've been warming up lately doing a bunch of double-stops using fingers 3 and 4, going from string to string to string to string, up and down the neck

What specific technical issues do you need to address and how do you deal with them?

[a22]

I find many string skipping exercises good for coordination. There's also plenty of difficult passages in bebop heads etc. that you pretty much have to do very slow at first with the metronome, gradually increasing speed. Sorry for not giving concrete examples, don't have the time right now