Just an update since I've had over a week of run time on this.
Again summary, was that I seemed to have video RAM problems that likely manifested under high heat. That's what got me googling on PS3 cooling, then found the YLOD info. Took action and replaced the paste but not pads or anything else. Symptoms were a little better initially, not completely gone, but less common during play. But certain games were worse than others, and one (my favorite game of all time) would consistently show graphical defects.
I resolved to try the pads and 19-blade fan before sending it off for repair. Three things I did differently, 1) new pads, 2) 19-blade fan, 3) used the 5 pea (4 very small peas on the corner) method for paste.
Although the fan sound is annoying (though getting more used to it) it's been problem free ever since. Granted it's only a little over a week, but I've clocked some hours on it.
So I'm a believe in the thermal pads and 19-blade fan. It's definitely making a difference. I'm not sure the paste method makes much difference at all.