That’s not what I meant.
I meant changing the reserve as a matter of policy after watching many auctions, not as a matter of gaming the system within a single auction.
e.g. Run a particular ad for 20 days and umpteen thousand impressions with a reserve price of $X. See how that’s working for you. If it isn’t the right reserve price, announce to your bidders that effective the first of next month the reserve price on that ad will be $Y.