I don't know the dimensions, they might be in the homemade dogbone thread in the FAQ.
I can tell you the 1G & 2G B12 links have different part numbers, as do the 1G & 2G B6's (none share the same p/n). OTOH, the links Holeshot sells claim to raise or lower either 1G or 2G B12's ~1.25" and 2" on the 1G B6, but will only lower the 2G B6.