For the protractors the general arm tube shape doesn't really matter - however, the arm geometry in particular may very well fit better or worse to certain protractors for certain major alignment variants and minor variations of these.
To get a better overview on that topic and a better idea of what you're doing, I'd suggest you to go to the "Tools" section of VE, click on "Cartridge Alignment Protractors" and first read Seb's guide. Next thing I'd do is to find out what the original alignment geometry chosen by the manufacturer might be (using JaS' alignment calculator pro with the tonearm specs provided by the manufacturer, possibly supplemented by own measurements...) - 'cause with the original geometry the cart usually will be nicely in line with the headshell, which is nicer for visual appearance, but just of secondary interest, if the original alignment geometry isn't to my liking... And the calculator results will also be helpful to check, whether a different alignment geometry would be possible on a certain arm with a certain headshell and a certain cartridge (or with a certain integrated cart model and without the headshell...). And then I'd decide, which alignment tool to use - i.e. either which protractor exatcly or which more or less convenient alignment jig or some abbreviation method like 52- or 49-mm-horizontal-distance-from-headshell-washer-to-needle-tip-trick for certain Technics and Pioneer models.
Hence, as the providers of that protractor you've linked to apparently didn't bother to name the particular geometry and inner/outer radius of the recorded area, one would first have to download it, check the null points and then use the alignment calculator to determine those (geometry & radii) by back-calculation. So I'd rather suggest you to use one of the protractors provided here on VE, 'cause these are better documented - thus, even if you don't bother to determine the original alignment geometry first and rather find out what fits by trying right away, you'll at least know, which approach(es) exactly you'll have tried.
Greetings from Munich!
Manfred / lini