Oh ok, yeah, that's more of what I would think. By common convention, your rifle "should" get at least an H buffer.
Unless someone pipes up with some data from an armorers course that 3 O'Clock ejection is proven to result in an X-percentage lower bolt life, I think it's a fairly academic "should", though. I'd probably do it (H, H2 or A5) just because I'm a geek and would want it smoother, anyway. I don't think it's anything to worry about IMO, though.