I've posted a few times that I question the "50/50 basal/bolus" rule... largely because it doesn't work for me.
Yet there does seem to be some correlation between basal and bolus amounts. I recently have had a few large lunches (estimated 200-250 grams of CHO). Bolusing is easy enough. Yet 5+ hours later, I end up needing corrections... and then tend to run higher during the night.
I don't know whether it's insulin resistance (and needing a larger basal), or if I'm simply releasing more glucose after being a glutton. It's interesting, though.
What's ironic is how steady my BG tends to be. If my numbers are good, yet I still feel stuffed: I mix a little Novolog with some N (about 1.5U of each), bolus, and check again in three hours.
That said, I tend to become sleepy and feel "ketone-clouded" (haven't checked for actual ketones, as BG is in range and I don't keep strips on hand) after such large meals. I generally avoid them; but, having had a few recently, thought I'd share my ramblings -- er, observations.