Probably a redundant answer given the previous answer, and probably in the wrong section too, but i was thinking about this sort of thing on my drive to work last week....
Has anyone done the maths? I mean, what are the 'tolerances'? Even in regards to honing with or without tape? I thought about this as I applied tape to the razor for honing but found the tape I'd got from 'The Cheap' shop was thinner than the tape I'd used previously (3M, I think). What actual angle differences are there given a tape thickness of, what, < .5 mm and a blade width of 5/8 of an inch? There are a few variables, aren't there? Such as pressure and tape thickness. I get the whole 'save spine wear thing', but I'm not yet convinced there's a real noticeable change on angles. I may need to do some trig....