If back off sets with an assistance lift works after a heavy single on the main lift... screw xyz, do what works.
I regard to the stuff posted on the bulgarian method I think its important to keep in mind that it is a system and not a template. And a system thats been in use for decades is bound to change from its original form be it the requirements of the lifter or the coach's interpretation. I've come across quite a bit of info by lifters who've trained under "Uncle" Ivan and it would seem the above statement holds true... the specifics of each lifters regime was different than the next even if the big picture appear to be the same: 2-3 sessions a day, 6-7 days a week, focus on the main lifts and only a few assistance lifts.
As mentioned in the quote before, I've come across a few example of the down sets being used for assistance lifts but one should remember olympic assistance work are more or less partial movements of the full lift. A full snatch to a power snatch as opposed to a squat to a good morning. I however came across more examples that showed the lifter working up to a max on the main lift and then reattempting the same load for multiple singles or doing down a little for more single and sometimes back up in weight.
Doubles and sometime triples don't appear to be used frequently because the technical requirements of a snatch/c&j at such a heavy load. And heavy loads are favor more so because olympic weightlifting is a very techniqual sport and the leverages and motions of the body in performing a 180kg snatch is much different than a 200kg snatch. IE: practicing 180 won't take you as far as practicing with 200.
Adapting the bulgarian method to the slow lifts is obviously open to much greater interperation. The main lifts are different, the depands of the lifts are different, and the slow lifts can be driven up by performing that same lift as much as it can be driven up by one that is completely different.
I do believe that the bulgarian method in its truest form can only be used effectively by those gifted and/or assistance. Beyond that, I do think many of the concepts of the method can be used by anyone with good results. It may no longer be the bulgarian method... but who cares. The strength community should be concerned with doing what it takes to get stronger, not splitting hairs. Most will never reach a point where there is an ultra fine line between to much work and to little work, the right selection of set/reps/lifts and the wrong selection. I suppose the point of this thread.