Well, many of your switches are intuitive. 10-5 and 10-6, of course you switch to 11 and 20.
And as far as the errors, hands per hour, etc. why not just play on a simulator until you have it down perfectly. Couldn't take more than a few weeks. Again, the goal here is heat-free EV, which is the holy grail of counters.
You could also think of the EV fractions as integers, which would make it easier to memorize. Like how we say a baseball player "bats 327" instead of .327. Just, thinking mnemonically, you know...