I think the REAL answer is to test the gun out and see how far it is actually off, clean verses fouled. That may or may not be possible any more, time wise.
I think you would be O.K. as far as oncoming corrosion with the dirty bore, going on two weeks before you get to it. I would never consider it without B209.
I myself don't leave the barrel fouled. I usually fire two primers into the clean barrel before loading and call it good.
In my testing the impact point from clean to fouled bore haven't been that much off, 1.5"or so at 50 yards as I recall. Many of my shots are right about there too, 50 yards give or take a few.
I just want to have a clean bore until getting a shot, then I may let it go three days or so after shooting, if out hunting.
Last Winter on an anterless hunt I called a coyote in with my predator call. He sat facing me at 100 yards, not about to come closer. I took him right through the center of the chest with my clean bored Knight 45 cal. It works for me.
Just looking again, 8 shots is a fair amount. Most would do one or two at the most.