Iuse the Allen wrench as my torque gage. Staggered tightening as suggested above is necessary. I do it over at least four steps. IEon the head there is usually 5 or 6 bolts. Holding the head in place bring down the screw so it is just touching the head Use the skip pattern and do the rest, Back to #1 and snug it using the small end of the wrench as your lever. Same pattern. Now use the long end and with your thumb on the upright pull with your fingers till you just feel some spring in the Allen wrench. Go over the pattern again. The repeat with the same feel when you feel the wrench spring just a bit, that is a tight as you need to go. When you loosen one of the bolts, they should snap when they let loose. It used to be good practice to go back and re-tighten the head bolts on a car after it had about 10 minutes warm up time. I've yet to see the need for this on our engines. The only screws I've seen loosen up were the set screw on the needle valve extension, and the exhaust manifold to head on four strokes.

The Allen wrench spring is goodup toabout a #10 in size. Mostof the head bolts are around 3mm so it works out just fine.
Don't forget a drop of oil on the threads before you start. They have been known to kind of weld them selfs to the head when put in dry.

By the way, a lot of the small torque wrenches, actually screw drivers, are a fixed torque. An adjustable one can cost nearly the price of ansmallengine, if you can find a used one. New, you can plan on well over a hundred, and depending on the wrench $200 might be closer.

Finally, the torque charts that I have been able to find usually drop of a about 1/4" or #10 size, so they are not much help for the screws we use.