Those 2 schematics of the ground scheme are deceiving. I would not use them for a 700B/II COMPLETLY WOPL'D AMP........ They may work for a partial wopl but not for one with a complete back plane kit, a complete control board kit, and a DCP from Wattsabundant.
Those schematics look like a 700 with a control board upgrade only.
IF, it was also back planes, it would show the ground point from where EVERYTHING gets connected (the center post for the left channel back plane......) When I build a WOPL, I have probably 7 ground wires which attach to the left channel center hole mounting point. There are a thousand pics here in the WOPL section showing that ground scheme. You gotta LOOK!