I have an aftermarket ( moto reva?) that I use on some bikes, I just compared it to the gates carbon drive as I was installing some aftermarket belts and the moto-reva was struggling to get a reading. In the end I found the carbon drive to be much less repeatable than the moto-reva in that there would be a wide variance between plucks. This may have been background noise but if it is Then I do not picture building a cone of silence for it.
I also find the aftermarket belts are much harder to get a reading than the oem belts, this does not mean I do not use/sell them as they are still a good product. I just know going in that they will likely have a harder time with setting tension, This is mostly with the 1000/1100 belts which unfortunately are the belts you have the least amount of leeway with. FYI: I have never seen as many belt failures as when the 140 spec was used on the 1000 motors. I think you will find Ducati revised that spec down to 110 because when the motor expands the belts become too tight and you can have a tensioner failure in under 1000 miles.
On old style motors I still use the Allen wrench method so if it is a 600,620,750,800 or 900 no other tool is used but an Allen wrench. I have seen all kinds of methods used whatever method you use be sure it is backed up by people who have been doing it for a long time and do it right and you should be fine. I have seen more than a few done wrong and know that it often ends badly for the engine and your wallet so take your time and do your homework.