I have tried live/dead/fresh kill, varied sizes down to 1 gram ASF, whole/split skull, warm prey/hotter prey/cooler prey, sented/rat/mice/ASF, zombie dance/left on the floor, morning/night/noon/midnight feeding, misting a few hours before actual feeding(that seems to get my fussy eaters going right away).
As for the regurged meals it always happened right after feeding or within a few hours of, sometimes as soon as I've stop pushing the meal down and I always gave plenty of time after each event before trying again (usually around 10 days in between)