Yeah the SPR is the size of the stack divided by the pot, so 200bb stack with 100bb pot is a SPR of 2 
Example:
I squeeze OOP and get called, pot is 29bb, I have 87bb behind and because of the board/dynamic/opponent/whatever I plan to barrel flop and shove good turns.
In order to have a potsize bet on the turn I need to cbet (effective stack - pot)/3 = (87-29)/3 = 19.3bb. The turn improves my equity and is a little scary for my opponent. Pot is now 67.6bb, stack is 67.7bb.
Now I think about villain's range. I need 33% equity vs his calling range for a profitable value shove. But in addition, he can also fold better hands than mine. How often do I think he folds? 10%? 20%? 30%? If so, I need even less equity vs his calling range and I can profitably shove wider, with a lot of draws.
I don't check the graphs in game, but I look at them periodically to have an idea how of much (or how little) equity I really need in those spots.