I have about that size prep sink, too, and got a regular-size, high-arc faucet for it. I am happy I did...I didn't want to try to work under a shorter/smaller faucet, and wanted a pull down spray.

I have 3 sinks in my kitchen and originally bought 3 regular sized faucets but one of the sinks really needed a smaller faucet due to where we had to put the faucet on the sink. I also wanted a pull down and found a prep pull down in Lowes. I am really happy with the size of it and am glad I found it. The larger faucet would have hung over too much. If you can buy the faucet and hold it in place you'll know right away.

I have a prep sink about the same size as yours. I got a full size faucet (Rohl country, low pull-out) for my prep sink, and had to return it and change it for a prep size. I had to pay a restocking fee. The full size had an 11" reach and the prep size had a 9" reach. I see la jan was unhappy with a prep size faucet with a 7" reach. In my laundry room I have a similar sized sink with a kitchen size faucet with a 7" reach (high arc type) and it's fine.

Can you possibly just order one regular size faucet now, and then try our your full size on your sink? You would have to order the faucets at two different times, but that way you would be sure to get the best size for your prep sink.

I used both sizes of Kohler's Vinatta faucet, and I am convinced it was the right path. My big sink is a 30" apron fireclay, the prep is a 14" square undermount fireclay, where the bigger Vinatta would have been much too large, but it's perfect to my eye at the big sink.
Casey

thanks all - this is turning out to be a hard decision. I'm currently considering a smaller sink so am now thinking the prep sink will be too big and create too much splash. I posted another question about that. Six months of planning and am still making last minute changes - argh!