1. Rather than zeroing the DAF on the naked bar, couldn't you place a straight edge across the tops of a few cutters to set your zero? Then pull the straight edge to measure your raker angle? Seems like it would do the same thing and save a few steps.
I've played with this but ultimately I guess it depends how far you want to go .
Ideally the zero reading should only need to be done once for the whole chain provided that spot is marked on the bar so it then becomes the reference place above which to take all measurements.
Using the tops of cutters either side of (or adjacent) to each raker as the zero position is the ideal zero position because that is the actual angle the wood is being cut. But this requires zeroing for every raker even if the zero is taken above the same point on the bar. I have measured the zero angle at the same place on the bar for adjacent cutters for new chain and there is a variation of +/- 0.2º, while for used chain with slightly different cutter lengths it's +/- 0.6º . Some of this (esp for the new chain) is because one is measuring on top of an object which is sitting on top of another and the small variations that produces - see below.
This zero variation of 0.6º for the used chain should indeed be added to my +/- 0.4º filing variation so my final actual cutting angles are indeed 6.3 +/- 1º which translates to raker depth variation of +/- 16%.. If this was a problem I would feel significant chain vibe/chatter and while I do see some it's about the same as when I use a regular raker gauge.
There are ways to reduce both zero and filing variations the most obvious one being making sure the cutters are the same length and more careful filing of the rakers. Either way, f one wanted smoother cutting it would make sense to rezero every time above every raker.
Remember the zeros have to measure carefully because of the ways bars curve and cutters slope, a straight edge can only sit on top of the outer tips of two adjacent cutters, the straight edge then is able to rock side to side, so both the straight edge and DAF have to be held square to the back support block. No big deal but I just found it easier to slacken off the chain and lift and pulling the chain away from the bar so the DAF can sit on the bar and take one zero reading.
2. Once 'we' have decided on the procedure, have 'we' decided on the target depth gauge angles for cutting, ripping, hardwood, softwood, etc?
Yep - The matrix is rather large. eg other cutter filing angles, engine size and power/powerband, type of chain, sprocket size, dirty versus hard etc. As long as I make big chips and don't bog the saw I'm good.