In order to achieve 'Genre Reassignment Surgery' (cruiser to cafe racer) I had an 18" rear wheel built, and am using longer shocks.
Figured the longer shocks would change the amount of belt slack the bike wanted.
So, I removed the shocks and moved the wheel/swingarm up and down to see where the belt gets tightest. Of course, it's when the front and rear pulleys and the swingarm pivot are in one line. Set the belt tension to almost zero at that point.
Put the shocks back on to see how much slack that translated to. The belt now has one inch/1"/25mm when the shocks are at full extension.
Wondering if that will be an issue?
Only solution I see is to use some sort of spring loaded roller on the underside of the belt. I think Ryca had some sort of thingie like that.
Anyone with long shocks and a belt have any grief? How much slack are you running?
thanks,
-Armen

If you support bike with rear wheel not touching the ground , remove shocks , remove spring from one shock & reinstall. Now you can raise swing arm to where shock is bottomed. Now you have max tension setting and exactly how much slack can be made by bottoming shock. Can you live with the slack ? How much sag at rear shocks with max weight on bike, that's your loaded sag. Getting to a point where you can find a happy medium of adjustment without using a tensioner. The belt has a little give/stretch to it unlike a chain. Belt might be a tad tight unloaded but as soon as you sit on the bike it is no longer tight. Might get a tad tight under some conditions like hard braking or getting airborne ( in my world airborne is fun ). As  your swing arm is compressed you get more slack until shock bottoms. Kinda how I found my sweet spot for chain adjustment and where tensioner is needed the most to keep it chain tight. Hope this helps , pretty sure you know more about this than I do.

Chain or belt it the same process finding where it gets tight and where it is slack and dialing it all in. Not too tight or too loose. The reason I made a tensioner is I built the tracker to take daily abuse ,I wanted it to be as versatile as a dual purpose. It eats up twisties,loves a fast dirt fire road & works ok on trails , even cruises at 70 mph & even does TT size jumps with ease. Like I always say "Trackers are for raising hell on two wheels"
Absolutely without a doubt one fun bike to ride !

Thanks for all the responses. I believe I have the correct info for how much slack I need to run, about 1" with the s/a extended. The question is, will that much slack cause any grief?