Thanks lutach. I have them installed at the moment, but I think they are roughly twice the weight of the bones.
I considered minimum wall thickness to be around .030, so I left some headroom going with .045, partly because I was concerned about distortion and "ring"- chatter, because you can only go so thin without having internal support when turning, and the ceramic insert I used was not liking it much. And yes it was a new insert.
However the narrowest point of the 'bottleneck' on mine is .030 thicker than the .170 diameter of the MIP bones, so I beefed it where it made sense to. I could have lost a few more grams drilling, but was cautious about drilling through said bottleneck. The heavier end is the inner end now as opposed to the outer cup on the old ones. Unsprung weight will be almost identical, not that it's a huge concern for me..... "weight is no object"
