I prefer to shoot my Tokina 10-17mm behind a 8 inch dome (I use Aquatica). But it really depends on what your shooting and if your going to travel.
For the tokina 10-17mm.....which IS the most popular WA lens for DX cameras and a better lens than the Nikon 10.5mm FE, you have a choice a of a few lens Domes:
Nauticam 9inch, 8.5inch,6inch, 4.33inch
Zen 9inch, 8inch, 100mm
The most versatile dome would be the mini domes like the Nauticam 4.33inch and the Zen 100mm as you can add an extension ring and shoot the Tokina 10-17mm with a 1.4x TC for CFWA. The Nautciam 4.33inch being alot cheaper and lighter than all the other might be your fisrst choice. There has been some talk that mini domes have an issue with corner sharpness when at wider apertures but this isnt an issue when your doing CFWA as your shooting with narrow apertures and having the strobes in close.
I personally like the larger domes for shooting larger subjects which i have locally but dont like packing them then going overseas.
Regards Mark