Okay so I am done shaft and casing swappibg with zeus's sg.
In short, no real use tbh.
Three other shafts fit in zeus's casings. All of them sit very low, meaning there's little ground clearance, and it's best to use wolborg 4/rock bisons base with them. Anyway, first is wolborg 2's, it doesn't seem to spin perfectly freely in there (there's friction between the tip part and the casings, that said it's not very bad), but it's probably the tallest of the three (good for eg bases), and most useful, you could probably make some kinda defensive thing outta it, but it'd be more of a "hey that's interesting" than anything that great competitively.
Second is dranzer s's shaft. It doesn't spin freely in there at all (very restricted) and can only use a single bearing (the too one). It's also a horrible tip and you'd have to use wolborg 4/rock bisons base to prevent major scraping issues when it inevitably tilts.
Lastly, there's wolborg 1's shaft and tip. Again only the top bearing, but it spins the free-est of the lot. However, only the very tip protrudes from the sg, so it is comically short. It can only be used in wolborg 4/rock bisons base and even then would scrape quickly.
Now using the cew-enabled shaft in other sg's. There are three sg's that fit the shaft, and one of those (driger f's) will only work in a base that doesn't fit the tip.
The shaft also doesn't fit through burning kerberous's base, and dragoon v2 and draciel f's prevent cew attachment (which in all cases must be done after putting the sg in the base anyways). This is a pain as cew's greatly increase the height of a bey, making tall, cew-less monstrosities, with no ability to use support parts.
The other two are wolborg 1's casings, which are a nice fit but only worsen the height issues.
The second is dranzer s's are shorter, but do not give enough clearance in uriel 1's base to attach a cew.
Bases: uriel 1's (supposedly a mirror of dragoon v's) has at least some way to make contact with the opposing bey (though the spikes are thin and fragile), but only works with wolborg's casings.
wolborg 2: works with both but again, hilariously tall even with dranzer s's casings.
Wolborg 1: like wolborg 2's but worse.
Basically, they're all just bait for upper attack.
The only relevant beys I couldn't check out were bearing stinger as a whole and dragoon v's base (which is supposed to just mirror uriels anyways).
The best thing out of all of it is probably wolborg 2's shaft in zeus's sg. Meh.
That said I had loads of fun fiddling around so time well spent methinks.
Oh, also, with a magnetic sg (needed.for normal configuration anyway), uriel 1's tip can be used with dranzer v's base. No idea why you'd want to but whatever.