I remounted and touched up about 5 knives. I found that as long as the blade is long enough to get the angle cube against I can get the knives to mount to within .5-.75 of a degree. The way I am using the sharpener it doesnt seem to really matter because when I start using the Micro fine or Super fine ceramics I am going to have to make micro adjustments to get the stones to hit the bevel flat regardless of how perfect I re-seat the knife.
On knives I sharpen for someone else I am just going to match the existing bevel most of the time. If you match the existing bevel it doesnt really matter if the knife is mounted perfectly vertical because you will be adjusting the arms until they match whatever the preexisting bevel is.
For me the only time I really need to make the knife is perfectly vertical is the first time I sharpen a knife that I know I will be touching up frequently. The first time I sharpen it I will set the bevel and than just match this for any subsequent touch ups.
