At some point before lunch today, I  connected and started a small turbo backed by an aux. cart at the cross connected to CP1's 10" gate valve.  There is a dry nitrogen gas connection at a tee at the turbo inlet and I am letting the turbo pump against the closed 1 1/2" AMV mounted to one of the cross' ports.  Tomorrow, I will valve-in the turbo to the cross and then admit dry nitrogen at the turbo inlet to test if the 10" gate valve leaks into CP1.  If no leaks into CP1 are observed, I will let the turbo spin down while letting the cross completely vent with the nitrogen.  The small turbo will then be valved-out.  Next, the cross'  8" CFF blank will be removed and a maglev turbo (backed by a leak detector) will be installed in its place and spun up. 

This arrangement will then be left pumping against the closed 10" gate valve until we can get time to continue hunting for the leak that is known  to exist somewhere around CP1 and GV6.