Try to get them a 10th mm thicker... 1.6mm because most of the cloners failed on part #17 making the ring where the o-ring should fit in, too deep. Especially on the rounded corners a 1.5mm o-ring will not be enough.
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Sockeye
I found 1/16 cs rings of comparable ID (7/16' x 1/16") too be to thick in the area between the corners to "make" it in.
1.6 mm = .0630, 1/16" = .0625
I feel it's better to go to larger ID but stay 1.5 cs up to the point where it either is to big to let the parts go together or is slack on the groove it fits in.
An 11 x 1.5 has to be stretched pretty far to fit on so it becomes thinner, (Just my

)
My 2 Ft type A clones that came with 10 x 1.5 mm o-rings (16) on part #17 leaked so I changed them to 11 x 1.5 mm and still leak some. Even used Teflon tape under it and still leaked after awhile.
I changed them to 12 x 1.5 mm about 36 hours ago and neither one has leaked at all.