On 2007-12-18, Robert Green wrote:

"When grounding bar kit is req'd, use kit PK 9 GTA for QO 12MW and PK 12 GTA
for QO 16MW and QO 20MW"

PK9GTA and PK12GTA I believe are the grounding bar kits for Square D's
current line of panels, so they should be readily available at your
local electrical supply.

When it says TWO # 14 or 12 CU what exactly is it referring to?

That the grounding bar (unlike the neutral bar) is listed for two
conductors of that size per hole.

I'm not sure which is worse: the neutral and ground being connected
by the steel case or a lone neutral being connected to the
supplemental grounding bar.

I would say the latter is worse, as it causes some neutral current to
pass through the enclosure case all the time, while the former simply
makes the case part of the EGC system.

Cheers, Wayne