There's not a huge amount of variance in OGs in my experience. They all weigh 4-6g which you adjust very easily by how much you trim/overlap/amount of finishing you use. You can also get manufacturing and weight variances between the same type of overgrip.
Replacement grips obviously vary considerably. I think you'd probably be better off searching for specific grip names in the sub-forum and adding the search tag 'weight' because as you say, there are alot of bread crumbs in alot of places.