FWIW 7075 T6 aluminum is comparable to 304 stainless steel (most common kind) in strength.

Since the axle on those is apparently oversized, I wouldn't be concerned. I've never saw or heard of a Phil hub axle failure in many years of wrenching. If it is a standard threaded 9x1 type front axle out of aluminum, that would likely fail eventually. (IIRC there were some in the weight weenie era, OMAS? ) I'm pretty sure that's not what they did.

If you're concerned, perhaps you could contact Schmidt or a knowledgeable Schmidt dealer and ask them for recommendations?