Most of the time, I just saw w/o a guide. Sometimes I want to use a miter box. I've tried to make one but they didn't work well.
I was looking at vintage miter boxes, not the crappy plastic ones that are sold now and I saw this https://youtu.be/BZI0qgLfkms on youtube.
A Stanley 116 miter box was (& still is) cheap. It's much better than the plastic or wood ones (IMO) and it works with any saw. So I bought one on eBay for under $20 & it was even in the original box.
It's limited in the thickness it can cut, but that's ok. It can do at least as thick as the plastic ones.
You sight down the saw holder to see your mark. It it's off by 1/64, you can't see it. It's very easy to position and the cuts in the wood don't matter.
I use clamps to hold the stock and maybe hold it to the bench.
I need to add a sacrificial board or just replace the board.
If you turn is around, the pull keeps it against the fence.
The cut is straight, vertical and accurate.
If you need exact, take it to a shooting board.
