I’ve done two hours at a time, for a couple months, until , I got blisters multiple occasions, esp when weight was 13-16 lbs.
.This was with the saber skin sleeve.
Currently have been using the fknMint sleeves for a few weeks and hang 60 mins , eleven to thirteen lbs and has been holding very well. FknMint also has a band that kind of seals the bottom, I used to use rubber bands on the saber skin , these seem better.