I think there are two basic things you need to look at with a jig, one is how you will work on it, and what it is for. One can make a jig that looks jig like, but if it doesn't do anything, what is the point. You can't really look at the architecture of the jig and say, great, if one doesn't know the build sequence, and what the jig will specifically do.

The other thing is how do you lay out on the jig. Ok, you have all these parts, which is the base line and how do you adjust the parts relative to each other. It's easy to have a finished frame and fit it in the jig, but what is your first point you set, and how do you work from it.

I have had a number of jigs. Eventually I got an Anvil. That jig is referenced off the headset end of the ST. One of the things I was looking for on the Anvil was a jig that could work like a drawing, so I could just dial everything in, and sorta look at it, and say, there is my frame. I was really disappointed when I got it and discovered, it couldn't be set unless one had some frame parts in it. Despite all the lucid scales, and all that Jazz, it wasn't really what I expected or wanted, and it wasn't big enough. Of course Don is a genius, he know exactly what he is doing, and what I perceived as disasters, I don't use it, were totally consistent with the build formula that he uses, which is very clever. So much so I have never heard it discussed, in tens of thousands of posts.

But my point is, what is ground zero on your jig, can you actually reference anything off of it. What is the build formula, and how does this jig support it. And possibly where is the seat tube end fitting. Building a jig is fine, building a useful jig is a lot harder. Quite a few people I have bumped into don't actually use their Anvil jigs, and it is because even that wonderful jig can be a miss, if you don't really do some serious thinking.