Does Everyone Use 2 Phono Cables with SUT

Sorry. Do you mean to differentiate between an "interconnect" and a "phono cable"?  If not, how on earth did you connect your SUT to your phono inputs before now?  To avoid using two ICs (or phono cables) in the SUT circuit, one option is to have flying leads (leads that are directly soldered to the primaries or secondaries of the SUT), so as to avoid any degradation due to RCA connectors.  Also, many use a single set of leads from cartridge pins to phono input, or in this case from cartridge pins to the SUT primaries.  Then you could have flying leads from the SUT secondaries to the phono inputs.

If you mean 2 phono cables as opposed to 1 phono cable into SUT and one "regular" interconnect out of SUT, then yes. The cable coming out of SUT is possibly even more important. Many line-level audiophile interconnects have far too high capacitance to work well in this role (SUTs don't like capacitive loads) - large gauge wires, over-the-top of shielding, braided geometries. Phono cables are optimized for lowest capacitance, so they work well with a SUT. Most Cardas interconnects also tend to have EXCEEDINGLY low capacitance, and are excellent in this role. You'll also want to keep this run as short as possible, under 1m, because capacitance is directly proportional to length

I've tried premium cables like a 1m Audioquest Fire or 1m Sky out of a SUT - it worked, but didn't sound as good as lower capacitance, shorter runs. The coloration effects of each cable became extremely apparent out of a SUT. Audioquest makes phono cables specifically optimized for low capacitance (Cougar, Leopard, Wild LP, WEL LP), and you should use these over their normal IC line. Leopard is quite good without getting into crazy pricing. Of course the AQ Fires and Skys sounded great between amp & preamp (where they belong). 

The Bob's Devices SUT cables are also very good for the money, and they're based on Cardas ingredients.

Mulveling you are spot on. I was using a phono cable “to” the SUT and a “regular” interconnect from SUT to phono preamp. I have a Miyajima Madake cartridge (.23mV output) and the signal was literally getting lost. 
 

I recently added 2 Audience Front Row “phono” cables and everything snapped into place. I thought perhaps my speakers were not efficient enough. I almost headed down the path to replace my speakers! 
 

Lesson learned.