Thanks Paul.
AATB,
A common gambling fallacy is to assume vig and payout are interchangeable. The payout is -121 per 100 and the the vig on the -121/+113 is 1.67%
This fallacy leads to a more comment and detrimental fallacy, high "laying more vig (in reality it is payout)" is bad. Not true. Laying more vig is bad (implying betting at books with higher theoretical hold retention), but laying shorter odds is not inherently worse.
Cetris Peribus,-3/-121 is equal to -3.5/+102 as far is EV is concerned. However, in its truest sense, laying the -121 is more prudent as higher percentage bets reduces the variance of ones bankroll, and laying -121 vs. the -110 is more prudent.
You are not saving "juice" by laying -110, rather shortening the payout structure at the expense of increasing your -EV (or decreasing any percieved EV).