If you want to just
check the valve clearance, you don't need any special tools at all for that. Just a set of feeler gauges (preferably angled ones) and probably a new valve cover gasket, if the one you remove is the old 4-piece cork style. There is an updated reusable 1-piece rubber type you will want to upgrade to unless it already has one, which it might if the head was replaced at some point.
Adjusting the clearance by replacing the shims does require special tools (tappet depressor and special shim pliers, plus of course a selection of replacement shims in different thicknesses to change the clearance), but just checking the clearance is a 5 minute job with feelers only and will answer any questions about the valves. And you're right to want to look at it, at some point, since this is routine maintenance that is important to do.
But again, if it sounds like it has even compression when cranking, then valve clearance out of spec is a highly unlikely culprit for no-start. I would suggest getting the engine running first, then immediately getting ready to replace the 20+ year old timing belt (!!), THEN during that procedure when the valve cover is off for the belt job anyway, planning to check and if necessary adjust valve clearances.
