What do you mean by "c-notch kit"?
The way I see it "shaving" the frame is to remove the top part of the hump that gets in he way of the bed floor, in effect making your about 4" channel frame down to 2" over the rear axle, and then you need something to add strength to what's leftover. (still not a fan of this idea)
If your goal is for more upward suspension travel, then the factory frame is good, and anything you do to it to get more only makes the clearance problem with the bed even worse.
What do you think of leaving it alone and making small covers in the bed to hide the frame that pokes through?
Or am I missing how this is supposed to work/not work?
Grigg