As I mentioned on your thread on the Samba, the twist method is quite subjective. Most of the belts I have seen installed by people not using the tension tool have been overly tight and most of the 1.6 engines I have disassembled have had trashed intermediate shaft bearings. Some have seen several pumps with worn out shaft bushings from being overly tight also. If you err on the side of too loose, the belt can skip a tooth.
Here is how I tension 1.6 belts at this point. With the cam sprocket loosened but bolt finger tight (sprocket can still turn on taper), cam lock in place, pump lock out, I rotate the crank CCW a few degrees. I then rotate back CW to TDC without going past. I then use the little pin wrench on the tensioner and rotate it clockwise. The proper tension is right where you just start feeling the springy tension of the belt. It is just a smidge past feeling no tension at all.
Personally I think that getting the proper tool is a very good idea. Use it and learn what proper belt tension feels like. I understand that when you are new to working on your vehicle the tools can seem expensive, but after you have been working on you cars for a while you realize that tools are extremely inexpensive compared to the cost of a failure that was preventable if the proper tools were used.
VW apparently agreed since they started building a tension gauge in to the belt tensioners 20 years ago. Just makes sense!
Mine is at a 45 degree twist on a 1991 1.6
At your next timing belt interval, pull the intermediate shaft out far enough to see whether or not the outer bearing is worn and flaking apart. If it is, you'll know the 45° twist method is crap and has cost you many times the cost of the tool. $90 is a pittance compared to the cost of the labor to replace the intermediate shaft bearings.
some people have said 90 deg twist, some have said as much tension as 45deg, i found at about 70 degrees my belt/bearings were howling, had to back it off some, that now changes the timing, well some,,. i find about 80deg of twist seems just about right. using tension tool.