Lee,
While your first approach might work, it’s quite convoluted to get it working correctly. I’d also suggest the bumblebee approach. Clean off any previous drivers and start from scratch.
That being said, if you’d like to another convoluted approach, here is what I did a while back on an optimus laptop when bumblebee was either in its infancy/unreliable or altogether non-existent:
[url]http://forums.accelereyes.com/forums/viewtopic.php?f=7&t=2045#p6680[/url]
(You can ignore any references to Jacket/matlab – the post was referencing a CUDA add-on toolbox for matlab) basically steps 2-5 is what you’d want.