There are other ways of finding TDC without a DTI.
There are indeed several other methods of finding TDC. You can do this with a u-tube manometer, there are whistles that screw into the spark plug holes, some people are good enough to get close using their thumb over the spark plug holes.
However, you must use the DTI to determine the point of maximum cam lift when setting the cam angle. Therefore... you're going to have to have the DTI anyway and using it to find TDC is the most logical method in this instance.
Thanks for posting the Mini Spares article link. I would like to point out one issue with it that is an over-simplification. They mention watching the DTI directly to determine when maximum lift occurs (for both finding TDC and the point of max lift on #1 intake cam lobe). This is not accurate. You need to have a general idea where the max lift will occur as described in the Mini Spares article. However, you need to use the method shown in the YouTube video for more accurate results. This involves stopping rotation at predetermined DTI values before and after max lift, recording the crank angles at these two spots, and averaging the measured angles. Both the cam and the crank are going to have brief periods of dwell at the "top" and it takes a very seasoned professional to know how to read this directly on the DTI. Using the before/after method and averaging the degrees read from the protractor is much more accurate for most of us.
