Can I please ask you a question about the Honda 4 pot calipers, namely are all the pistons in the caliper the same size diameter?That is my biggest beef with the original caliper - lack of availability of high friction linings, which is why I adapted a CBR600F4 caliper to my fork leg. I run EBC HH code linings in it. The stock cast iron Norton rotor is a great match to these linings, and with a 1/2" bore master cylinder, a 1-2 finger pull will haul you down from speed with controllable authority. It is a very inexpensive set up, and requires no permanent modification, so it easily returned to stock if preferred.
The piston area of the 4-pot Nissin is about the same as the stock Norton Lockheed, but it does move the piston centerline out about 1/4-3/8" for a marginal moment arm increase. There is also enough room in the caliper to accept the stock rotor and unworn pads without any machining.
The HH friction code linings are the key to this working. If some were available for the stock caliper, the transformation would be incredible.
FWIW
The reason I ask is because I don't think Honda do a smaller diameter on the leading piston causing slightly more taper on the pads than need be - not that I'm saying they don't work, I've been using some 1980s ones for years.