Very cool work so far. Makes me wish that I had access to a machine shop.
I'll be watching the rest of this build with anticipation.
Keep up the good work.
The lollipop end has enough support for a QR axle so it isn't pulling against the QR alone and more importantly the tug end sits flat against the dropout , ie it doesn't wrap around in any way .
When you want to remove the wheel you just loosen the wheel nuts giving plenty of room to pull the tensioner away from the dropout . With the tensioner out of the way it gives enough slack in the chain to unloop . At no point does the tensioner need adjusting . When the wheel goes back in : with the correct phase relation you will have the same tension as before you removed the wheel .
Im sure you could make your own , if your sticking with a solid 10mm axle you don't need the QR support so its just a alloy ring thats needed , bit of threaded bolt and most importantly a flat bit of alloy for the end and a nyloc nut . You could use a long cap head bolt instead of the nut but they have a habit of working loose .