I was not aware of the GRS hammers. I guess they are making their hammers for the same reason I made mine designed like that: Just a simple lathe turning. At least their handles approach a suitable design better than most of the stuff I have seen. At least,they could be reshaped ahead of the bulb some.
How long has GRS been making those? I made mine in the 70's. The "graceful" hammers were made in 2003.