Cable help with SET amp

I am currently venturing into the world of SET amps coming off of a Bryston system. At the same time, I am moving my system into a different room and require longer speaker cable lengths. i have been trying to do searches about various recommendations but still have some questions.

I am using a Bryston DAC, Mastersound Compact 845 driving Pioneer S-3EX speakers (88.5 db, 6 ohm). I need 14ft lengths.

1. With a SET amp, do I need a smaller gauge cable than normal? my research seems to indicate a smaller gauge is preferable when using high efficiency speakers with a SET. Not sure if this is mainly due to the efficiency of the speakers, specific attributes of the SET or a combination of both. i realize my speakers do not likely meet the high efficiency standards.

2. Does the 14ft cable length impact the gauge?

3. Is single cable or biwired preferred with SET / mid efficiency speakers. And is the gauge impacted by that preference. ( i.e. I am assuming a shotgun biwired cable of two 5 gauge cables would be overkill where maybe a single 5 gauge cable would not)

4. does the 14ft length have an increased adverse affect on the sound given the SET or efficiency of the speakers.

5. I'm not looking for any specific manufacturer recommendations but for an example, Cardas recommends their SE-9 cable (9.5 gauge) for SET and efficiencies below 95 db vs their typical recommendation of their golden cross (5.5 gauge).

Any input is much appreciated. Very few places around where I live with expertise in tubes or trying to sell the most expensive cable they have.

Thanks