Do'oh, after being one of those chanting "i want elf book for things like high elf magic careers", I was reading my pdf of Career Compendium from 2nd edition.
It's clear there that its approach was that elves can be wizards just like humans, taking the same careers, and only when they get to Wizard Lord rank are they ready to enter Tower of Hoeth and learn "real magic". They mechanically use the human careers but without any college-based social requirements etc.
Teclis taught humans the "juniour, training wheels" one-colour of magic elves learn in grade school (so to speak) and master before learning true elven multicolour magic. Given their lifespan, that makes sense. An elf can "start out" by developing what takes a human a lifetime and move on from there. In the 3rd edition's "rank sense", a Tower of Hoeth graduate would thus be 1-2 ranks or more above the highest rank Hero's Call has in the system. So a Hoeth graduate would be an epic NPC not a player character. That fits nicely with the historical fluff about Teclis and others being so powerful, if they are masters far beyond the common Hoeth graduate.
For player character high elves in 3rd edition that means, I could see them taking the normal wizard careers. It might be nice to do "slight variants" of advancement options in the careers to reflect the different cultural approach. The 2nd edition approach also provides an automatic "character retirement" explanation for high elf wizard - after they finish last career they go home to Ulthuan to "learn real magic".
I think that means only Wood Elf Spellsingers really need special treatment.
Apologies to any who already arrived at these conclusions/realizations.