Long time 23" Ultimate owner. I've experimented with many approaches to "radiant heat". I wouldn't double the basket splitter.
I'm a big fan of the 23" ULTIMATE DOUBLE BOTTOM DRIP PAN. It makes a great heat deflector, and an easy to clean drip pan when lined with foil. (Some people use the drippings for gravy, where the double bottom helps prevent scorching.)
I use it as a heat deflector for pizza. Using any ceramic cooker as a pizza oven, one needs to confront the "heat from the bottom" effect. Wood-fired dome pizza ovens don't work this way. The best deflector helps here.
Long ago, I'd get several years at a time out of a giant unglazed plant saucer (no lead risk) lined with foil. Again, leave several inches around the outside.
The real art to radiant heat is to time the fire's arc. Cook on the return from "low earth orbit" when the fire is waning but the dome remembers.