With all due respect to Bogie's excellent dissertation (I'm a fan too
), another option is to remove the lifters for cleaning one at a time
, replacing each one when done cleaning before removing the next.
The reason I say this, is I have sent the circlips flying off into the ozone on several occasions when disassembling/reassembling them- and that was w/the lifter out in front of me on a towel w/good lighting. If that happens and you're working on the lifter still in the engine, losing the clip would be easier to do and could even find its way into the hole at the end of the valley, the distributor hole or into an intake port, etc. Obviously those holes could be plugged up, but the whole thing is too much bother compared to simply removing them one at a time IMHO. This also gives you the opportunity to inspect the lifter foot for abnormal wear.
More info on the lifter disassembly is here