I can't help with the first one. I don't know of a way but there may be some glitch some people know about.
The B-Spec pit strategy is a simple trigger point for what strength level your driver will come in to pit and change drivers(assuming you have multiple drivers in the race). If you set it to 10%, he'll drive until his strength drops to 10% and then pit.
It does work... sometimes. I've run races where it went flawlessly and my drivers were actually ready to get back in the car after only two of the three other drivers had done their stints. I've also had them be nowhere near back to full strength after all three others drove. Not really sure what makes the difference.
It also doesn't matter that much as long as you are watching the race and issuing commands anyway, as you would in an actual competitive race. You can let your drivers continue to run around with no strength and they don't get substantially worse than they are at 10 or 20%, at least if they are not rookies. So you can pit in for tires or fuel just like in a-spec. If the race isn't competitive and you're just walking away while it drives at minimum pace, it will automatically call them in when it thinks the tires are shot or fuel is about to run out, so there's no need to set the strategy.
If you do let it run with a strategy set without watching, there's a chance you'll end up taking way too many pit stops if they only run a couple of laps at a time. If you do that with only one driver, I think he'll pit every lap once he reaches the limit.
Nice idea, poorly implemented. They're good at that.
