Problem with a 2' High block wall is you really also need an 8-10" thick footing, below the frost line if you want it to last.
On the curve, if the radius isn't too tight, just open the joints and fill in with cement.
It may be easier to pour concrete wall, if you can rent forms. You are only looking at about 4 yards for a 6" thick wall, 3' high, 63' long.
What are you using on top? I assume 'face it with stone' means using a 'cultured stone'? They usually don't have much in the way of capstone.
I know it's not want you asked about, but I've used this on walls, very happy with it, dry stack looks more like stone than most products. techno-bloc:
