Paul; I think mounting it flatter would solve your issues. I have my F2r mounted pretty flat; I have to move back slightly when standing to see the odo, but not too much. And I never noticed not seeing the tire.
I'm always standing in technical terrain anyway, so I don't think the roadbook would make any difference.
Of course ideally the odo would be above the F2r, but until I can afford a Rally Moto Kit, this will do.