Green grit wheels used to be used a lot in the early days of carbide, before diamond wheels on ebay were available for cheap.
Green SiC wheels do not really grind carbide, they erode the binder in the matrix and chip out the carbide grains at a microscopic level. Without a rigid machine and flood coolant, it is hard to make much headway or do accurate work with one. The wheel erodes really fast for offhand work on carbide. I used to use some about 25 yrs ago both freehand ind in a cutter girnder, and would never go back. The only one I ran that was sort of cost effective was a 20" wheel in an old Fitchburg cylindrical where we spun in port tools after rebuilding them. A 20" diamond wheel would have been prohibitive, and would have been worn out prematurely grinding partially on steel.
To start experimenting, get a 220 or so grit diamond wheel off eBay and do the corners freehand as others have suggested. It is pretty fast and easy. Before using the diamond wheel , grind the steel back of the carbide out of the way on an aluminum oxide wheel. Grinding steel with diamond wears out (clogs and erodes) the diamond wheel rapidly and is not effective.
BTW, carbide dust is not good for your lungs. Seriously. Use coolant if possible, and an adequate respirator.
smt