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Back when i soked my naniwas the 3/8 combo would open about 1/16" in both ends,
the 20mm 1 and 12k did not appear to be effected the same way
Now that im not soaking my hones it dont seem to be an...

Mixing hones from different brands or series is usually not recomended sinse they can work werry different from each other (if you want to learn to use naniwas, then buy naniwas)
Lots of people here...

id suggest the 3/8 combo then the 1 and 12k should fit on either end