You could just use a one inch travel dial indicator. If US, make a conversion table from Metric. There are many ways to clamp the indicator, only limited by your imagination. The delivery valve needs a special socket ($28?). There are several ways to turn the engine, but the Baring tool is probably the easiest. Just about any type of Bar type gear puller.
I pondered this over and over again. Finally just paid the $250 and bought the Miller. You still are not finished. As I recall, you need a 32MM socket for the gear nut, torque wrench for the nut, about a four foot extension for the baring tool. I think when I was through, I spent about $350.
I have the Miller. I prefer it over the Snap-on. My Miller kit had no puller. I use a bar type puller. I prefer it over the Snap-on. With the bar puller, you can clean the gear and shaft without removing and reinstalling the puller. I don't think you can do that with the Snap-on. I also use the bearings that come with the Miller.
In my neighborhood, it cost about $250 to have the timing set one time, and then to stock only. A fellow TDR member will set the timing where you want it for $100, but he is a 3-4 hour drive. I think this is very reasonable, but too long of a commute.
If you buy a Kit, it is a great loan item.
Wayne