You might also take a small part of your design and scale that to run small tests before burning entire planks. I’ve saved myself a ton of materials by taking a chunk of a part with a sample slot set, scaling that and cut/testing, then going back and scaling the whole model only when I have it dialed in.
Unfortunately you’re up against what I call a “minimum complexity problem”: getting a really tight fit has lots of variables, it’s not possible to make it simple and also highly accurate. It’s a bit like the adage about quick, cheap, and high quality—pick two.
For instance one major set of variables that almost can’t be automated is in the material. How thick? How consistent? What’s the kerf width? Glowforge tries to eliminate that as much as possible via proofgrade — even then there are small variations in thickness and kerf width that will require iterating if you are going for a very tight fit.
Depending on your tolerances you can mitigate this with slot designs that are designed to pinch or lock your materials, but again, minimum complexity rears its head and now you’re back to needing a serious editor.
This is why there are whole companies dedicated to making capable editors (fusion, inkscape, illustrator). It’s a complicated issue and requires detailed tools.