The new tracking tips are an improvement as is the advice on shimming the grips. Our experience of easing the grip friction so they drop under their own weight is it makes the whole tracking procedure easier and the ship fly smoother. We've been doing that for years now.
Some years ago I made a Laptop based track/balancer. Main rotor only. It uses a couple of modules with accelerometers in 3 planes and fires a strobe. I've used it successfully on quite a few ships over the years.
I have often noticed a problem with old/assorted/repaired/repainted blades. (plenty of them in the UK!)
It is most obvious at the hover stage. Once the hover is set to 0.2 ips (or less), if the tip targets are strobed they are usually tracking nearly in the same plane. If the aircraft is then landed and the tip path observed with no pitch applied at the same RRPM, a well matched set will be still tracking the same. The rest of the procedure is easy and the ship will fly well.
However, I have seen several times big deviations at flat pitch with tip path splits of 3 or 4 inches, yet close tracked in the hover. These blades are almost impossible to track. They either fly well in the cruise and are horrible in autorotation or are a lumpy compromise in all phases of flight - and it takes hours to get it that 'good'.
I'm sure on new ships the blades are right but it seems 'it' goes out as blades age, get painted and get swapped over the years.
The 'it' is chordwise centre of gravity.
By matching the chordwise c of g of all 3 blades, it is possible to correct this problem and get the ship to fly smoothly, easily. It can be done with paint (in theory), by substituting a blade or by redistributing weights at the blade tip ( I know,
) My first aircraft had 2 'A' blades and 1 'U' and it was a pig when I got it, but once set up it flew beautifully until one of the A's started to debond. With a smooth flying ship a 2.5 inch trailing edge debond was immediately obvious although not alarming. I scrapped the blade.
My second ship had a set with consecutive numbered blades but was bad. Again with a little effort matching chordwise c of g, we got it silky smooth.
I suspect if the chordwise C of G is way out, the blade is getting towards end of life and should be carefully watched for debonds, or scrapped.
I'm certain that a mismatched set makes for a poor ride and hours spent tracking.
I picked up a set with consecutive numbers and only 260 hours TT to replace my odd set so I'll be interested to see how they fly when my 28 takes to the air again in just a few weeks.