when hopping off the trapeze, i usually curl my pointer finger to hold the string.
if you do an element after the brother mount, then that element may benefit from your choice to use your thumb, pointer, or middle.
landing on the back string or both sort gets you back to a trapeze setup. since your learning tricks in this area, you may want to try this green triangle as an alterative to trapeze-to-brother you can also practice trapese-to-gt.
