Unfortunately, I wouldn't have any idea where to start building something like that. I'm already holding on for dear life just trying to get my arduino code working with Simpit.
Perhaps adding compatibility with some of the more popular mods that add resources (TAC, Near-Future, etc) by hard-coding them could suffice. Or requiring TAC Fuel Balancer, as it already displays fuel data of stock and mod fuels, and building the new version off of that. I have no idea what is possible nor what is easiest, though.
In other news, I think the stage tutorial is broken. It works, but it doesn't work twice, so it stages once and then gets stuck (requiring a reset on the arduino). I think it has to do with the "buttonState" not getting reset to LOW, but my attempts to make it work perfectly are in vain. I was able to get it to work well enough by adding:
buttonState = LOW;
delay(1000);
after the stage command in the same IF statement. This doesn't work like the space bar, since it will just stage every second if the button is held down, but it doesn't get stuck at least.
If this was brought up previously, I apologize. I've only read through about half of this post's comments and hope to finish reading soon.