Done it on my wife’s bike. Fox transfer cable actuated post.
IF you are running a 1x set up you are in luck. Use the cable entry to the downtube previously used for the front mech cable for the dropper cable. Then down to BB, around it and up in to seat tube. Loop appears tight externally but is fine in practice.
Result is really neat and tidy – almost factory! You do have to drill out the cable stop in the front mech cable entry point – but dead easy to do and if you are 1x anyway you don’t need it do you?! Would work equally well for Reverb but with a little more bleed faffing.
If however you are not 1x you are going to ruin the lovely clean lines of the scale with an external routed flapping about monstrosity… 😉