Well Iam late to show on this debate but I wanted to drop two cents in anyway. I have had some issues with the western form (P.d.deppei) doing poorly over the coarse of the past 11 or 12 years. I do not think that meal size or type is as criticle as temperature. Meal size comes into play in so much as if you feed a very large meal and then do not provide a thermal gradient for the animal it may have trouble digesting. But a hairy meal or a large meal will not inheirently end in regurgitation.
A herp friend of mine, Rob and I were discussing husbandry one afternoon when he made the statement, "Snakes spend thir entire lives eating, breeding, avoiding predation..but mostly adjusting their body teperatures."
I had always kept my animals at roughly ambient or room temperature but after dealing with some chronic low grade issues such as a normaly present GI bacteria blooming and creating problems and in another case some animals getting psuedomonus,also a very normal widespread organism, I realized that although my animals where doing ok my husbandry technique was not optimal or ideal.
I lack the resources to keep individual groups in the exact parameters that their wild counterparts would deal with, however I now provide them with a pretty significant thermal gradient. The heat tapes are set to 110 F and the room temp is set to 76 F.
They probably stick to the cooler side but they have the option of getting their temps up if needed to increase activity of their imune systems or speed the digestion of a larger meal. The heat tapes are on timers and run for about 4 hrs in the morning at sunrise and another 4 at sunset.
I had a lot of reasons for rationalizing not setting up a thermal gradient (cost too much, the snakes are at an ok temp., not set up to provide it....etc.) in the past but I am totally sold on it now and really do not have to deal with regurges, etc. anymore.
My formally problem groups such as deppei, jani, lineaticollis, vertebralis, deserticola are all bullet proof right out of the egg. They eat good sized rat pinks and fuzzies right away. If I were asked what I thought was the single most important thing a pit keeper could do to have good luck with his or her animals I would say provide a wide thermal gradient.