Basically I'm going to do as You stated, But I need to sit down and figure out How I'm going to Prep everything as if I am going to immediately use Phase Change on the CPU and Chilled Water Cooling Not Only on the VC's, But Also on the MB Blocks.
I may end up as Q56 stated and put a thin coat of Vaseline with a Heat Gun over the Entire Board to start with.....or, I may try the Kneadable Eraser, But it is going to take some serious thought on my part as to exactly what to use.
Regardless of WHICH method I end up using, Vaseline will DEFINIELY go inside the CPU Socket until "Hell Freezes Over"! It has Always worked with No Problems on My other Sub-Zero Rigs, so I see no reason not to continue this practice, Except for making sure if I use Both Kneadable Eraser AND Vaseline, I Don't let the Two Touch together.
As to Single Card Benches, I have Only used a single GTX480 when I first got the ASUS for testing, and then I put Both KPE's in when I got them this past week.