I have both. The G10 is pretty much the same thickness, however, the G10 is more rounded at the radiuses. Eric confirmed that this is the case for most batches.
My guess is that the scales come a certain thickness and are CNC shaped to pretty much the same dimensions regardless of material. Then hand radiused and tweaked to fit each knife by number prior to the knives being coated...... * That is my guess as to how it is done.
.... Out of curiousity, I went ahead and pulled my calipers and both knives.
If I measure at four of the same spots on the handles:
*** G10 at front/ricasso area: 0.705"
*** micarta at front/ricasso area: 0.691"
G10 behind front pin: 0.690"
micarta behind front pin: 0.711"
G10 behind middle pin: 0.696
micarta behind middle pin: 0.721"
G10 behind rear pin: 0.695"
micarta behind rear pin: 0.715"
So, the G10 (at least on mine) is a hair thinner than the micarta. And 0.02" is about a hair thickness. I don't know if someone can feel that little amount of difference in their hand. The radius is noticeable in the feel of the hand, but the radius would not affect kydex too much (????).
However, 0.02" isn't too much even for micarta, but it still might just slightly affect the tightness of a micarta sheath. It should still work, but might be a tad tighter on micarta.
It should not be a factor in most leather sheaths unless it was a drop in sheath and was already tight on the G10. Then it would be even tighter on the micarta.
I don't have a great answer for you. I am pretty particular about how I like my kydex to fit. But, I see a lot of differences in how some people make them. I have seen some blade pressure fit kydex that is very hard to move the knife in and out of. I don't like it that tight. I have seen others that rattle. I don't like it that loose.
I would probably have someone with good references make your kydex sheath. Describe in detail what you like for fit and send them your knife.
..... I didn't know Eric made sheaths... (?????).
