Ratherbflyin, I am not speaking for Cal but I have had a fair amount of experience with flaps on TF warbirds (not the Spit however). Most of them tend to be a bit heavy so, when you drop your nose in the landing approach, they can pick up considerable speed and float forever in the flair. To avoid this problem, a longer, flatter, slower approach can be used but this can lead to a "dragging it in on the prop" scenario which increases the chance of a stall Which usually will be VERY abrupt with a wingtip drop.
With flaps, you can drop the nose without nearly as much speed increase, keep some power on (better control), fly down to about 6" or so above the ground, chop the throttle and watch it sit down. If you have mis judged the speed and are a little fast, the flaps scrub it off quickly. I fly a circling descent path from the downwind leg, continuously nose down ( much less chance of a stall) to the flair. It works out well for me and besides, it is the way the big boys at Oshkosh do it. :-)