Don't Relieve B4 setting

I had read the Strat blurb on this in awhile, but every time I do I come away confused on how to set my Pitchers "don't relieve B4 setting". For instance I have D Martinez in the 70s who is an S8*, I have him set for F8 but after reading Strat's description I feel like I should change to F1 or F0. Please refresh my memory, thanks

Pitching at F1 or F2 means he`ll pitch completely exhausted--unless your bullpen is crap, I wouln`t go lower than F7-F8

You do not want starting pitchers pitching when they are fatigued. F8 is the least fatigued F1 means your pitcher is dead tired.