I bought a Hotglass seat off Ebay complete. It had been mounted on several bikes so there were some extra holes. I wanted something better than the 2x4 wood I have seen on other bikes so I started thinking about how to mount the seat. Having adjustable mounts is always better and I wanted easy access to the batteries and tools, so this is what I came up with. The mounts are elevator bolts with furniture leg rubber pads on them. The lock is from AutoZone and is a hood lock for a car. The inner fender is a galvanized 12" trailer tire fender that I cut down in length. It fits really well between the frame stubs and will replace any strength lost by cutting the rear loop off. I mounted the tail light to the back of the fender so I do not have to hassle with any wiring. The forward mount is 2 fender washers with a .250 spacer between them and attached above the rear tank mount. I used an extension bit and drill block to pick up the hole for the lock. I upsized the hole for the lock stud and tacked a nut to the inside of the fender to locate it and then welded the permanent nut to the top. So mounting the seat is simply a matter of sliding it on the front mount and lining up the lock and turning the key 1/4 turn. I left the original pics in for someone wanting to use the seat like a street tracker. I have added some more to show what I have now.

As with most things, weaknesses are found out after use. I revised the mounting system adding more mounts later, and added a rear frame loop to mount a real rear fender. The seat still goes on and off the same way, it just has more support.
I have painted the fender black and mounted the seat wit rubber well nuts rather than the velcro supplied. The last thing I need is to have the seat fly off when I stand to go over a bump. I am happy to say the least.