tt ground to phono section. solid copper?

As long as your ground wire has good contact and continuity, solid core or stranded wire will not make a difference. 

The looping issues are why the ground is optional. :)  Listen and that will tell you.

I agree either solid or stranded will work, 16 gauge should be more than enough.  You may also want to try the really really cheap ferrite beads on either or both ends ($5 for a pack).  May do nothing, but cheap. :)


Erik

The ground is there to make sure the tone arm (which shields the cartridge wiring) is properly grounded so it won't impart noise to the signal. Any wire will work fine.

     I have to have a ground on my vpi classic it buzzes like mad without it.I had it straight to my pre ground phone inboard.I am switching to the external phono,It has a ground terminal and a 2 prong dc conversion plug.My question is would it benefit me to go from it it to my pre ground also because the plug is not grounded ? The reason I asked may be a novice question,I remember when grounding large things to earth like a hottub a solid core wire is used it made me curious.Yes I use a 16 gauge stranded spaded wire now.
With acoustic zen matrix reference 2 cables which made a huge! difference over the blue jeans( another thread entirely) night and day ...