Michael Constable
TVWBB Fan
I'd think with the drip pan on the lower grate, without the water pan to shield it, would burn up the drippings. If you nested a shallower foil pan inside of the deeper one (with the same length & width), then you'd have some kind of air gap there to minimize burning. This is all in theory, though.
EXACTLY what I'm thinking about doing this year since I'm so paranoid about my crisp Turkey skin but I want to try drippings from the smoker which I have never done.