Sarge, on the related tokens page I see each of the 4 smaller ones listed as ~.6 ozt and the larger one listed as 4 ozt.
(4 * .6) + 4 = 6.4, so I'm not sure where you are seeing the discrepancy?
I will say that the smaller tokens are slightly larger than a $10 strike. If you measure the silver inserts, you'll see that they are slightly larger (by ~1 mm). I didn't remove mine from the capsules to measure the thickness, but just eyeballing it they look to be the same thickness as a $10 strike.