I bid for him as if he were there on the floor. I act as his agent. If the floor bid exceeds the high mail bid, I stop bidding and the floor bidder wins the lot. There are no games and everything is rather straight forward. Strange situations can happen such as two bidders who bid way more than a lot is worth or a lot that sells too low, but these are the exceptions.
Most lots go for prices that are fairly predictable.
In most cases, I receive a number of bids at the same amount or all clustered in one area. I had no choice in that situation since the two top bids were identical. We don't charge for photography, insurance or for other things that other auction houses charge. This is a labor intensive business despite computers. What about the in-house photographers, layout artists and lotters.