If I remember correctly, you had (or still have) a 630 Byers? I was wondering if you prefer that guitar for Bach, or if you find it easier on the 640.
It's hard to say like better or not. To me it's really a matter of trade-offs. I do like the 630 Byers, but there are some aspects to my larger guitars that I like better. More space on the neck makes playing easier in general. But there are some passages in music where I appreciate the 630 for that extra skosh of stretch-ability. I don't dislike the modern all-wood lattice on my Byers, but I gravitate more towards the traditional fan bracing sound of my GVR. Each instrument has its own personality and I like both for what they offer.
I will add that one of the best things that happened with I got a 630mm is that it made me appreciate my larger guitars so much, even 650mm. And that's not to say I don't like the 630mm.