I also gave up on finding the ideal grafting knife. I also gave up on any
knife with a bevelled edge-- couldn't get the hang of using it, couldn't
make decent cuts with a tool I used so infrequently.
I always end up doing the season's work with a good, sturdy, decent quality
paring or kitchen knife ! Freshly sharpened, of course. If a section of
the knife edge is very straight, that's where you want to cut scion & stock.
I find it's easiest to use a knife which I'm familiar with, and
comfortable using, rather than a "professional" tool just because it is the
"correct" tool.