or just use a manual boost controller

 

If there were only three items available to log, I would choose AFR to see how close the mix is to max HP, RPM to compare slope as a means of how close spark is to MTBT, and knock so you still have an engine left to enjoy the power

But theres more than just 3 variables to choose from, and sometimes you can get better precision from sources other than OBDII/MUT (more work setting up though)

 

I didnt even think about you using an MBC which you, obviously are... My bad! I have spent soo much time reading "ecu controlled boost", that I forgot people still use MBC's... Well ****, that makes life a lil easier...