Checking and adjusting the valve clearances was laughably easy on those engines too! For what it's worth, when I did the 900SS belts I used the Allen key method of checking tension. I did use the old "twist through 90 degrees" method on a Golf once, again without problems, but on the Ducati the Allen key method felt a lot more precise to me, although I accept that the other methods are even more accurate.
You can do a twist method, i think it was 45 degree twist. But the guitar tuner is the easiest way I found. I downloaded an app called "gStrings". The frequency of the new belts needs to be 110hz (+-5hz). Run the app, select "tune auto" and pluck the belt. Apparently the original Ducati tool used a similar method before they changed to a laser alignment one (or something like that i read at the time). I double checked this with the allen key method just to make sure and all was good.
Although it will be a used bike it will obviously come with 12 month warranty and fully serviced before I take ownership. Out of curiosity I asked how much future maintenance costs will be and was stunned when told that a basic service (oil & filter replacement, plus fluid/bike check) would set me back £275. I remember when the 848 was launched. Didn't Ducati at the time make a big thing about slashing servicing costs for these and subsequent models?