Yes, I have an electric full lock up clutch. I love it. Mine is actually not a Horton, it's some German company. It actually works a 2 speed setup using a set of permanent magnets to provide a small amount of drag for a low speed and then a full lock up via an electromagnet. Basically the same setup as the AC compressor clutch but a touch bigger.
There is a Horton part number for an IH app idi that has the correct LH thread. I had to make an adapter insert on mine because it looks like it was mis boxed - the Horton part number very clearly specs a LH thread, with a different part number for the RH PSD clutch. The number on mine crosses to the idi LH one, but the thread was actually RH.
Making the adapter was fairly easy on the lathe. I did have to take the clutch completely apart which was fairly easy on mine. I have not laid eye on the Horton setup but I expect it would be about the same. Once you have it apart it's a fairly straight forward operation to machine it out, make an insert, weld in and then cut a new thread. I do not think it could be done without a lathe though. That thread has to be concentric and full depth - too hard to get it accurate without the lathe and a tap is going to be tapered (not full depth) unless you get a regular and a bottoming tap and use both.
Biggest problem with using the Horton clutch is the fan backspacing - the IH app puts the fan about 2" further forward, so the Horton clutch does the same - basically it mounts where the front of the stock clutch is vs the back of the clutch flange. On my clutch I was able to mount the fan in essentially the same way because of the clutch design but I don't think you can with the Horton. I do believe I had found a Horton fan that would fit though, IIRC it was something like $200.
I had also looked at adapting some other type of fan clutch probably to mount on the pulley flange but would need some custom fab work to do that as well. Biggest problem is likely to again be the fan back spacing - the truck is very tight here and most other apps have more room.
IMHO the best option for a fully locked up fan would just be to fill the clutch up with silicone fluid.