Rappel here At 48, but I’m sure I’ll still be doing at 60 if all goes to plan. If you hunt from your rappel line as a tether, and set up on a mechanical to avoid switch your line (where things can go wrong), good idea to tie a quick alpine butterfly below the device (mammut, gri-gri, safeguard) while you hunt, or have a backup friction hitch. These devices are designed for belay and rappel, not designed to hold you in place for 6 hours, and sometimes when you put slack in the system while standing up and putting on layers, fiddling on the platform, you can get some slippage. of course, you’ll need to untie the butterfly before you descend.
one disadvange guys don’t talk about is gnarly, limby trees can cause some annoyances in line retrieval, especially in the dark. You‘ll learn to flip the rope, walk at different angles, etc to make this easier With practice. It’s not a major factor, but some of the guys doing 2TC are opting to shimmy down with tethers (rather than rappel) to avoid this step And the weight/bulk of the rappel rope.
My early season method will be 2TC, but late season is 3 stick, movable aider with rappel. Rappel allows more aggressive stick spacing, since you don’t need the scary night time movable aider descent.