First off, as mentioned before, thanks for your service
Those links are to the actual tensioner that is bolted to the engine and is an integral part of the timing belt system.
The 83-86 cars had the eccentric tensioner roller that was pretty simple to use although you have to use the P9201 tensioning tool to find the right tension value. The 9201 is probably what you were thinking of. it runs something like $625 new so it's quite an investment as far as rarely used tools go.
the 87-91 cars had a spring loaded tensioner that once you had your belts on you would release the nut holding the spring loaded tensioner arm and it would put a force on the belt and then you tighten the nut and it holds the arm in that place. Some people don't trust it. I do. No, unfortunately you can't put it on an early car.
Personally, I'd recommend for someone who has never done the belts to do them with the "twist method" and take it straight to a Porsche shop and have them tension the belts and make sure you put it together right. It will cost you something like $100 but it's worthwhile at least on the first time.
Other options are the "cricket" tool and the arnworx 902X. Many people here use them and they work good for the timing belt but as far as I know, you can't use them to tension the balance shaft belt.
Jackson