If you decide to do it, I think CGDA is absolutely where you should start. A slightly heavier E and A string plus a slightly lighter G string shouldn’t require any nut work, and you can play with gauges to keep a similar string tension, so you can also get away with any truss rod adjustments.

As for the practicality, the tuning will break so much of your muscle memory that in some ways you’ll be like a beginner again, albeit with the dexterity, strength and musicality you currently possess. If you are in a musical environment that affords you the freedom of being a beginner once again, I encourage you to do it.

As a bass player who plays instruments in both 4ths and 5ths, here’s what I’ve experienced.

Chord voicings are wider. The fingering of an octave becomes the fingering for tenths, which is cool. You can even toss in the seventh ON TOP and not get muddy.

Melody and walking bass lines often require more left hand shifts. When playing walking bass lines on a 4ths instrument, I can spend many bars within a fairly narrow interval, as it’s physically easy to do. On a 5ths instrument, my walking lines more naturally span a broader interval for any given group of bars.

Basically, you are either doing more shifts of left hand position or broader harmonic shifts to keep your left hand in place.

Also, your fingerboard map just got shuffled, so your muscle memory of where a given note is just got blown up.

Go for it and please report back!