How important is position scarcity?
In auctions position scarcity isn’t a pricing issue. Even in shallow auctions.
The key is making sure that the pool of valued players for the auction includes only players who can be bought in the auction. In a 12-team league with two catchers, that means 24 catchers, 12 first basemen, 12 second basemen, 12 shortstops, 12 third basemen, 12 corner infielders, 12 middle infielders, 60 outfielders, plus the next 12 most valuable hitters. Once you have that list you can then scale your prices up from the least valuable player, almost certainly a catcher. At that point you’ll have 168 hitters worth $2106 (if your hitting budget is 67.5 percent. Every player will have his right price for this auction, no need to adjust.
Position scarcity is an issue in drafts because you always have to consider not only the pick you are up to, but also the next one after that. If you want to take an outfielder with your pick, but all the elite shortstops are going to go before you pick again, you have to decide if that outfielder is going to help your team more than taking one of the shortstops and an outfielder later.
One other issue to consider: There are fewer competent catchers and shortstops than outfielders and first basemen. If you lose a shortstop to injury or trade, you’re much less likely to find a reasonable replacement than if you lose an outfielder. Does that mean you should spend more or less on the scarce positions?