gif4445, you've identified the factors that I've been thinking about myself. I think I can keep the combined weight for pad, bag, and bivvy below 1 kg (Klymit makes a couple of inflatable pads that are ludicrously light; I got one on sale through REI). I know I'll resent every gram of that as I drag it up the hills, but it seems like a reasonable insurance policy even if I decide to sleep mostly in hotels. My plan is to split hotels and camping roughly 50/50, allowing that I may change my mind.
I won't be a contender in the GC unless I ride beyond my abilities and everyone else has bad luck, but I do want to make a good accounting for myself.