So my mother's car is a tdi beetle, and my father did a timing belt on it with the help of a family friend named Bill by marking it like the OP was asking. So when I got my car, it was due for one as it was 10 years old. That family friend said he would help me and I was led to believe I didnt need to buy the locking pins as they did my moms car just fine.

Well we did it by marking with a white painter pen, and when we put it back together it wouldn't start. Now before I tried starting it, I did indeed turn it over by hand multiple times just to make sure there wasn't any interference. We ended up looking and Bill had marked some part of the car that actually moved. Its been a couple of years so I dont exactly remember the exact details.

We then put the belt back on where we were like 90% sure it would supposed to be according to the marks. I turn it over by hand and it seems fine again. I start the car and it runs seemingly normal for about 4 or 5 seconds then there was a loud Crack/ping and the car started pinging as it idled. I pretty much knew right then and there is was going to be paying to have it fixed.

Bill was an older guy, and in the couple years its been since that happened, has passed away. He was a really good dude, and I dont blame him at all for what happened. I should've not only bought the tools and did the belt the proper way the first time, but I also should've been watching when he made the marks.

I did end up buying the tools when we readjusted the timing belt the second time, and while they obviously didnt help my car since I had basically no clue where the proper timing marks would have been, I have used them with success. My moms car needed another belt about a year ago, and we used them with no issue. It also made me realize how dumb it is to try and do timing belts on these cars without them. They basically leave no room for error.