advantage or disadvantage going biwire vs single

Probably not...but if you want to try biwire, experiment with cheap wire. If you don't think there is a difference you will have wasted few dollars.

I biwired my MG1.6 using small, AWG24, (cheap) wire for the tweeters so as to eliminate need for a tweeter padding resistor in the crossover. The sonic change, if any, was slight, but I do see some benefit (probably completely theoretical), and, being lazy, I have not taken the trouble to change back.

I bi-wired my Tannoy's for a while with decent Synergistic Research speaker wire. I've since gone to single wire (Dimarzio) and a quality (Onix) jumper. I like the sound better. It might be the cables. There is the train of thought that the two sets of connectors are really only for bi-amping. Because of the internal X-overs, separate wires don't add anything, only separate amplification. I cannot afford to bi-amp and the differences i heard bi-wiring were subtle, at best. There aer those who will swear by bi-wiring and I've no argument with them. Bi-wiring is a trial/error thing for each set of speakers and cables. Some speaker manufacturers even encourage bi-wiring. I don't believe there is a right or wrong in this situation. Have fun.

It usually depends on the speaker design.

Some speakers come with high pass and low pass filters (crossovers). With this design, biwiring usually makes a huge difference.

I envy you guys that can use just one cable. I tried mine with one cable compared to what I now use and the difference was night and day. My speakers prefer QUAD wiring.

The key here is to experiment, and ask others with the same speaker. Now, with audiogon, you will probably get a lot of feedback.

Good luck,
Richard