Wow, that's a significant amount of displacement and I can now see the point of having those 'tabs' now. Do you think it's necessary to have the tabs exposed or very close to the edge of the cap, so it is somewhat adjustable?
Ideally, I would love to find a 'suitable' razor that has good rigidity and with features to align the blade, so the exposed tab is not necessary. But I don't know whether different brands of blades would have large enough of size difference/variance that this feature is actually necessary to ensure a good shave.
It depends on the design of the razor. Fatips use alignment pins the same as Gillette Old Types. All razors that use that pin system may need to have the blade aligned when loaded, even the Merkur 34C.
Later razor designs, like the Gillette NEW types, have a different design and the blade has never failed to be perfectly aligned every time in my experience.
Blade alignment is really a minor gripe and its easy to overcome. Sometimes, as is the case with Fatip, at the moment at least, is the blade sometimes needs adjusting.
Blade type, while there are a very minor differences in hole spacing, makes no difference really.