I'd make a final offer and let them decide every single time.
Regarding Option A, I'm not comfortable with massively overpaying up front with the sole intention of hammering them in post-DD negotiations. I know it happens in both real estate and non-real estate transactions but it's just not for me. The only exception would be if the number is VERY VERY close to my desired price and I could present legitimate, concrete reasons for concessions after due diligence. Even then, worst case scenario I'd probably still be willing to pay the initially agreed upon price.
But with the numbers you're talking about? No way. I'm not comfortable ethically and it's hard to imagine the seller going for it in the end either. Which brings me to Option B....
After the bidding war, the seller should know you're a serious buyer. Everyone has a final price and you hit yours; no harm done in walking away. If the buyer believes that's the true value let them overpay. If they try to get all sorts of significant concessions you've left the door open for the seller to come back to you at the price you actually want.
Just make sure to end things cordially with the seller if your final offer is raised by the other party. Let them know you can't afford to pay more than $X, thank them for their time, and ask them to keep in touch if the property goes back on the market. Maybe they call in a few weeks, maybe in a few months, maybe not at all. Some may disagree, but that's how I'd handle it.