hmm ... going all the way back to 1e, Githyanki are
Fighters , Magic Users
wizards , "Gish" the original Fighter+Wizard ,
and Anti-Paladin (of some sort) either LE or CE, I guess NE is possible too ,
and of course a sprinkling of Psi.
Ur-Priest fluff is nearly perfect, since Gith only have a Lich Queen but no gods.
So going RKV that way is fine.
Using a Silver Sword for that single strike Glass Cannon bye-bye Astral Plane hit, is right up a Gith's alley.
Fighter 1 / Erudite 7~ish or so / Illithid Slayer 10 ... I mean this is the basic Gish already, with Erudite slightly more wizard-y.
I don't think going so far down to that old school, would even consider what ToB is at all.
But you can, ToB being far better game design than anything strictly 1e based.