Found this forum at some time last year, however, forgot to book mark it and it's taken ages to find you again.
I run a vfr750fv, and have followed lots of posts, regarding shim stacks, I stripped my forks at the weekend, to find that the shim stacks were, not as those listed
on here as standard, I also had a set of vtr firestorm forks which were bent, and are good for shims, so with this in mind i have rebuilt the shim stacks, and used 5 wt oil,
I would be greatful if someone could cast an eye over the stacks, and comment as to how you think they are, I have not refitted the forks to the bike yet, but the rebound seems to be very adjustable, but I'm not sure about the compression stack.
So I see you are looking for a second opinion. I'm guessing you'll find the same advice as I've given you: there really isn't much performance to be had from the Showa 4-port pistons. I can certainly understand how tempting it is to want something for nothing - that is our culture these days - but I think you'll find without the correct springs and valving pistons there is no shim stack in the world that will do anything for you.