Ugh. Finally got around to this. The Ratio tuners are not labeled correctly. They are supposed to be 1 through 6, but one side is labeled A,A,C and the other side is 1,4,4. Waiting to hear from Graphtech. In any case, the pegholes need to be reamed slightly. On the bright side, the invismount plates will fit the peghead screwholes, if you slightly enlarge the plate's screwholes.
Gotoh Kluson replicas don't fit through the Japanese ferules. The butterbean buttons look the part, from the front, at least. The Kluson-style tuner body does not conceal the original screwholes.
OTOH, Grover openbacks fit through the original ferules, and cover the Japanese tuner screwholes, but you will have to drill new holes for the Grover's mounting screws.
It looks like you might be able to buy the cheap Chinese angled plate tuners, and disassemble them. Then you can flip the button shaft to the other side, to get a drop in tuner. What quality of tuner you end up with is unclear though.
The upshot is most people who want a better tuner, with a minimum of effort, should just go with the open back Grover. It's a better tuner, and a cleaner installation.