I have not done it on an Adv, but have done on my own 200EXC, 450SXS, 520EXC, 250EXCF. So much better control over the rear brake. Going down steep hills, skid steering, walking alongside over bogs etc, its all good.
I use a combination LHRB and footbrake by adapting the rear master cylinder to get fluid fed through it from the LHRB.
For the actual LHRB on the bars I use a scooter rear brake or the Brembo clutch master cylinder as fitted to later KTM EXC/SX models.
I have fitted dozens of Rekluses and LHRB since 2002.