Btw the original question is not a way ahead way behind situation. It's a slighty ahead, way behind situation and therein lies all the difference. So if you have 10% equity 50% of the time and 65% equity 50% of the time you have a combined total of 37.5% equity - i.e. you are behind his range so checking is correct (as your EV calc showed)

And yeah, ranges and EV for sub ranges combined into a neat EV number for lines you could choose to play against his range anticipating specific reactions to specific betting lines. All you can do is decide on a line, decide what is reasonable that the opponent does and start crunching numbers.