I figured a way to get the full 13 bit resolution of the PWM and now I get the full value range. I figured that my timer counter being 8192 is just a shift of 13 so I can avoid overflow by not shifting up 13 and down 10 but rather just do the entire calculation with an additional shift of 3.

The ADC on the face of it is a lost cause, it is only 10bit accuracy so I only get a change every 8 values of the PWM. I need to look at ADC averaging, I started to think about it and wonder if it's worth spending time to do it. I currently take a snapshot of the ADC and need to average it out anyway but originally wasn't planning to use fractions in that average.

I did some code size reductions and the code is now at 7860 bytes. It was at 8100 beforehand and got down to 7600 and then the new PWM accuracy took more space. I kinda like the serial text interface but not sure how long I can hold on to it in its current verbose state.