Geezmeister,
I DO have much experience doing long wet incubations (I'm not really sure the term "reflux" is correct for this method). Three years ago when the two hour pyrotechnics trick as per Worlok and Methhead was the only thing anybody at the hive discussed, I was doing 16 to 48 hour runs at 180F. It was the only way I could get it to work - and it worked damned well. I also performed a number of experiments running flasks with identical ingredients, side by side, at the same temp (180F), varying only the durations of their runs. I never discussed these on the board because I felt stupid about the whole thing. I then went to experiments with higher temps and shorter run times. In attempting to discuss them at the Hive, I was just really turned off by the arrogance a certain moderator who presents his opinions as fact, without providing any substantive support of his position. So, I gave up. Now, maybe I will try to present my point again. I am a very patient individual and I don't have problems waiting on long reductions per se. But from my viewpoint there are two aspects of the long "reflux" that could (and will for someone, eventually) result in the worst kind of troubles a clandestine lab chemist can have. The chemist should constantly be aware that we are in guerilla warfare with the authorities. And that's my first big concern. The whole time a reflux is going the chemist's ass is hanging out raw and naked. If the cops come to your house for say DV, or your stereo's too loud, or someone requests a check on your wellfare, or for any fucking reason at all, and they happen to see or smell something ... well, then you're cooked. Maybe sounds far fetched? It does happen. Listen to a police scanner for a while (which anyone should be doing every second they're in the lab anyway) and you will see. It's simply a matter of probability, and the longer you leave yourself vulnerable the greater the risk. Now if you're the type that just leaves all your lab shit lying around instead of hiding/removing it post reaction, then this point has little bearing on you.
The other major concern with these long runs is that when we're talking about 24 hour, 48 hour, and 72 hour run times it is obvious that these runs almost always are going to have large blocks of time in which they are left unattended.
I have done that many times, and it scares the hell out of me each time. There is so much to go wrong. Crashing into your set up as you nod off trying to stay awake is not a good thing. And I have done it. But at least I was there to take care of the problem. What happens when you're not there and the flask breaks/explodes/implodes and your red phos or hypo or phosporus acid starts on fire? If the house burns to the ground with you or your family in it, then nothing matters. But if you're lucky and no one gets hurt, and even if the house is mostly spared, you're still going to have to contend with the fire department. Which means you're going to be seeing the police, because there is little doubt that the FD will be able to determine the cause of the blaze. What if the hose comes off and you've got a really misty one cookin'. Will the neighbors smell it and maybe call the Hazmat unit? Or worse, what if you're sleeping in the lab and out of the hose spills a bunch of phosphine. The potentials list goes on and on. What solves all this and cuts way back exposure time is a wet hotter rection. A Rx done at 185F that requires 3 days is finished after about 4.5 hours at 255F. This is not conjecture. I have performed it and it works. I still go for 3 hours at minimum regardless of the precursor quantites, just to make sure. As for quality, I believe it is indistinguishable from that of long lower temp wet run. IF a slight degrade were detectable I still think the tradeoff would easily be worth the safety edge one realizes in doing a short hotter wet run. A strategy I have tried that works as well is to due the early part of a run for say from 4 to 8 hours at 190F then go to 255 for 2 or 3 hours. This would be equivalent to at least a 36 hour run done entirely at low temperatures. Considering that the reaction rate is much greater during the earlier hours of any run, you may have reacted two-thirds of the precursor during those 4 to 8 hours at your "preferred" lower temp anyway before you jack up the temperature to 255F to finish up. Once the MA is formed, going to 255F will not affect it. I've also tried slowly ramping the temperaure. Starting at 175F and reaching 260F at the very end. Works fine too.
As for aziridines, this is not a problem. One of the papers available at Rhodium's site shows a chromatograph of a run a group did at 265F. It nicely shows over time the PE peak decreasing, a concommittant increase in the MA peak and a steady decline of the aziridine peak until it no longer existed after 5 hours, having been converted to MA.