You’ve already covered a good bit of ground. My own work with a very nice customer in the wood industry has revealed my personal strengths and weaknesses. I’m not a person who focuses on one aspect and not the others. You have to make sure you have the appropriate skills for the situation.
For example, there is no “correct” age for joining a board if it’s not an older board. You could try joining a younger board, but the risk is much more likely to wear out/fail. (Some boards will be more prone to this than others)
My work shows that joining a board has some inherent complexity:
The boards that need to be joined usually have quite different surface structures.
There are different types of joinery tools, like a wood clamp or other piece that can be used to secure the boards. If you don’t have the appropriate tools, you could risk failing.
Using a “taper punch” (the metal end of a punch tool with which the metal points are cut off) is much better than the “tap punch” (which works by punching out a flat spot on the wood)
A wood chisel or a tool with a flat edge that is sharp enough to remove the wood and put a good edge on the joinery is a necessary tool.
You need enough knowledge to ensure that you have the tools for the job, and adequate knowledge to ensure that they are used.
If you are an experienced woodworker, you will already think through the details. And you will be able to identify those details in seconds.
The last point is important, too, and it’s the point where the whole process can fail. If you use an incorrect technique, or fail to follow a correct cutting guide, you have a possibility of damaging the joinery. And there is a real risk of damaging/wasting time with this kind of joinery.
Do you need a computerized computer program?
No. The only way to create a very effective computerized joinery guide is to use a real woodworking tool that will be used to cut and join the boards.
So how do you get one?
You need a computer, and you need a good one. The software that I use is a combination of SolidWorks 2003 and Maya 3.0, and it saves you a lot of time by automating a lot of things. All the other software solutions out there are not as easy to