I wrote a whole paper on doing this, several years ago. If what you have is like that, then sounds like you came up with a similar thing.
Only thing is, under my approach you don't need to know which "node" you're looking for, to a shooter that number doesn't matter a whole lot.
The initial entries I use are your OAL, known barrel length, and MV (chrony or a what-if). The xls then shows whether you are "close" or not, to a node. This way you can vary your powder load in order to get close to the node, and not waste a lot of shots in the in-between "no-mans' land"...
Only thing is, under my approach you don't need to know which "node" you're looking for, to a shooter that number doesn't matter a whole lot.
The initial entries I use are your OAL, known barrel length, and MV (chrony or a what-if). The xls then shows whether you are "close" or not, to a node. This way you can vary your powder load in order to get close to the node, and not waste a lot of shots in the in-between "no-mans' land"...