Could you do periodic auto-update of tags? Maybe then an excellent solution would be to display both indicators through a slash, for example "123k / 567k"?

Unfortunately calculating the tags takes a lot of effort, so it would slow the game down if it did it all the time. You can update the tags yourself using the command /resource-map-markers mark (see the mod description for more commands) which will clear and recalculate all the resource markers.

I would also suggest a periodic update option, similar to autosave; or even when this is done.