I wouldn't try that if I were you - that's an awful lot of grinding! 3/4 sq HSS is tough stuff - and do you have the height to accomodate it?

Better would be to use a bit of thinner gauge plate or an old file - in the latter case get it red hot and keep it there for several minutes to soften. Then you could form the profile and harden. You might get away without to rake if you take it slow and use lots of coolant. Of improvise a kind of "inverse ball turning fixture" so you can use an ordinary turning tool and move through an arc.

Easiest if you have only one to do would be to form the curve by a series of small steps then smooth out with a half-round file.