Yesterday spent the day rappelling. Rapping on a 7.5mm is spicey, mostly because my ogre hands can’t get a firm grip on the brake strand. Added friction and a third hand VT was nice. VT prusiks can bind on a twin 11mm rope. The rope needs to be tended and the number of wraps matter. The VT under heavy load will want to spiral the twins so you have to keep the strands parallel. Luckily unlike a normal prusik it can easily be redone but transferring the load needs to be puzzled out. Also setting the VT higher will help when passing the knot on descent. I had set it too close so the space between the VT and the knot once it’s passed wasn’t sufficient. Would I ever rap a twin 11? Probably not but the goal was to experiment and learn