I think that the round core Boomers came out after the Balanced Nickels, and the CM3050 flats were not initially an option as a set, but were introduced along the way.
RBCs were there before BN; however, the "balanced construction" concept wasn't applied to RCBs until sometime after the introduction of BN.
The Precision Flats CM3050 set was introduced sometime between March and September of 2017.
Also it seems that D'Addario's balanced sets came as a response to GHS Balanced Nickels, though am not sure whether or not D'Addario mimics the equal number of windings from string to string in the construction, or just the overall diameters and tension.
D'A came out with their "balanced tension" sets way before the introduction of BN, and they're strictly about tension, not about construction or even tonal balance.
However, as part of his responsibility at GHS, he has to walk a fine line between tradition and change
My hope is GHS won't start fixing what doesn't need fixing for the sake of innovation. I do understand the idea behind this balanced construction concept, but the difference it has made in real-life applications (at least for me personally) is not night-and-day.
If I could pick out one specific feature that I wish GHS would start applying to more than one model, that would be the "roller-winding" method. As a huge fan of the Pressurewound (Alloy 52 rollerwound), I would love to see the same concept applied to other models. Rollerwound Super Steels, Rollerwound Pure Nickels, etc. I would take that over "balanced construction" any day. But that's just my personal wish...
