Why not just build your own pointer? You can do as 69340 Cuda and but the proper timing tape (it must match the damper diameter) and then build a pointer. Alternately, you can calculate how many degrees per inch on your damper (it's easy) and scribe the damper every 5 deg or so. Setting up TDC is easy Just build yourself a "positive stop" from an old sparkplug--or buy one. You screw the stop into no1 plug hole, and wrench the engine around 'til it stops. Temporarily mark the damper under the pointer--that you have built--and then turn the engine around CCW untils it stops, and AGAIN mark the damper under the pointer. EXACTLY halfway between the two marks on the damper is TDC. then all you have to do is either install your timing tape, or scribe the damper and you are not only done--but now you know the marks are correct.

Bear in mind the pointer you build doesn't have to be a tab or have any numbers---just a sharp pointer to index in reference to the damper. It doesn't matte where you put it--so put it where you can SEE it. Then build the TDC and other marks onto the damper to suit.