Probably easier than the see-saw would be just the standard rod and holder system, widely available. If you can find the long version (Volvo/Audi) style you can screw it right in without it interfering with anything at all. If you can only get the short version (intended for VW 4cyl diesel) you may need to only remove the vacuum pump for clearance.
As noted above, the method of timing by rotating the pump may "seem" easier than using the cam sprocket method at first glance, but once you have done it a few times, you realize it is actually far more work. Dealing with the fuel line connections, four pump fasteners that have to be repeatedly loosened and tightened with each timing setting attempt (of which one, the upper inner one with the inhex head, is quite difficult to access), etc, etc. Versus only one fastener (the rear cam bolt) that is easily manipulated, and lets you reach your desired timing setting usually on the first try since it is much more precise.
It sounds more tricky that way, but if you can get your technique figured out, you'll see the reason we all much prefer that method here.
The pulley holder tool, 9995199, is still easy to find and cheap from Volvo, so don't let that be an obstacle. You can also home-build a similar tool as ngoma suggested, OR use one of the many generic "sprocket buster" tools out there, which work just fine. Here is an example, many others exist:
https://www.idparts.com/sprocket-pul...81-p-6247.html
However as you pointed out, the method of adjusting is secondary to getting a timing reading in the first place, that is certainly true.
Remember to disengage the cold start device and then rotate the engine a couple times afterwards prior to taking a timing reading attempt, otherwise it'll throw you off. We've all made that mistake before, in many cases more than once!