Suntour LePree on a late 3x8 drivetrain, good idea?

So in the process of looking into options for my MTB gearing issue, in which I butt heads with the mechanical limitations of conventional 3x drivetrains, I ran across the Suntour LePree derailleur, a super-wide-range low-chain-slap high-ground-clearance system from the mid-'80s that apparently only failed to take over the world because people considered the odd looks to be a downside, unlike me

And I also ran across one of these rare relics for a somewhat reasonable price online...any reason not to replace my Shimano Tourney TZ with this? After spending a couple bucks on different jockey wheels for the TZ, I found that it has non-replaceable jockey wheels (insert facepalm here), one more issue the LePree could fix right away...I'd be running it with an 8-speed Shimano indexed shifter. I've found reports that these can work with 8 speeds with a friction shifter but no reports of anyone trying 8 speeds with an indexed shifter - should be no problems there though, right?

Well I bought it...if it doesn't work out, I'll add it to my collection of oddities well-suited to a recumbent bike with a freaky drivetrain, or worst-case I could fix it up and flip it. The biggest potential issue I've found so far is that it may not be designed for very small sprockets in the rear, so the upper jockey to rear sprocket distance in the higher gears could be large.

So after ordering it and posting some questions on a vintage bike board, I found that this derailleur probably won't work with any indexed shifter...but I will do some testing with it when it arrives.