This one seems to get the best reviews as an add on.
I have a built in on my 36" range, but when I do need more griddle surface....

The 12"x20" will fit easily over two burners on your Wolf, but you may be able to fit the 14"x23" with a little overhang. (see the pic of the 30" Jade)

Congratulations and happy cooking!

Here is a link that might be useful: Chef King Griddles

This post was edited by ctycdm on Mon, Jun 2, 14 at 10:56

Griddles come in different metals that have different properties and are good for different uses.

Cast iron or steel-
These are poor conductors of heat so can be uneven but hold a lot of heat. You can really crank up the heat and they will be great for searing meat where it is hot. Because it can be uneven, it can have hotter and cooler zones which some like. They are heavy. They also will take longer to heat up and cool down so slower to respond if you want to turn up or down. Some might eventually even out, over time. Some report that theirs never even out. They will season easily and become non stick. Some cast iron griddles are reversible with a grill side too. I think most of them are smaller though. Consider that CI griddles might be sand cast and rough and will take awhile to season. The steel ones are smooth.
There are add on and portable versions of the steel griddles.

Aluminum-
This is a much better conductor of heat. If you are cooking a lot of something it will cook very evenly. It is very responsive when changing heat. It can take a seasoning and become nonstick but takes a little more time. It is much more difficult to find a naked aluminum griddle. Most are non stick which eventually will wear out. They are relatively inexpensive though.
Royal industries griddle
The aluminum griddle is an inch wider than the Chef King. It also comes in a non stick version. It is lighter weight than the Chef King but both are the same thickness.

I have had an aluminum griddle on my old stove that was seasoned well and nonstick. It was too small for the new one so I gave it to my sister.
I have the 23x15 inch Royal Industries griddle and it fits on my Wolf range perfectly.. I have the island trim and the bottom hangs over a bout 0.25 inch over the end of the grate. Because the aluminum has such good heat transfer I can fill it with sandwiches and it will toast each one perfectly. I also have another aluminum griddle that came with a previous range. it is nonstick.
I do have a couple of large cast iron and steel skillets that I use when I need really high heat. Pick up the steel griddle if you go that route and make sure you can lift it.