Two things I would like to articulate about my experiences with what your about to do, first is the fork oil. When I installed my seals I used Seans video and it made things a whole lot easier. Your on the right track with ATF or PS fluid but more specifically
Import and
Synthetic. I know the other stuff will work but Morley was pretty specific about import synthetic PS or ATF. All I could find locally was a Valvoline Synthetic Import ATF, so I used it. From what I can tell these fluids range from 7.5-10wt. I'm really impressed with the feel of my bike now, I did install progressives at the same time. I prefer a ride to be on the soft side than the firm side because I do long rides and often find shitty pavement quality (and sometimes dirt) in my adventures. It's feels more like a modern bike now instead of harsh and twitchy like it was.
The other thing I want to mention is the inferior nautre of aftermarket seals, among other parts. Chinese seals are made with inferior rubbers, materials and workmanship. Never ever ever use Chinese aftermarket on your fine Japanese Vehicle. It's not worth the savings. I buy my OEM (Original Equipment Manufacturer) parts from boats.net or from Morleys Muscle right here on this forum. Not only do I have the Vmax but also a Yamaha Venture, Lexus LS, Acura CL and Suzuki Samurai and one thing that is true across the board for all of them is the OEM stuff fits, functions and lasts far better. I have tried to save $ multiple times on my Japanese vehicles and it's just not worth it having to do the same job twice. I'm not sure which seals you got but I highly recommend snagging some OEM seals and covers before you do the job.
Here is the video
https://www.youtube.com/watch?v=ZKKdbwMQ5fY