Great to hear that DAX is "clicking " for you and you were able to solve your own problem.
Matrix totals and subtotals can be a big challenge because even in the simplest case, you have four different evaluation contexts to deal with. Here’s a detailed post I put together on this a while back that I think may provide a useful framework for you to work through your remaining issues.
- Brian
P.S. Thanks for trying to format your posted DAX. Here’s a trick - if it won’t format, try adding a hard return after the “=” in the first line of the measure and then try to format everything after that hard return line. That worked perfectly when I tried to reformat your posted measure.