Depends really how your party is set up. Garuda really only needs 1 tank but if you're only tanking Garuda I'd be aiming for ilvl 60? That way you're not getting carried by your healers. Solo tanking Garuda and the red add I'd be aiming for DL/AK mix.

If you get a tank drop in AK you get at least 2 pieces at once (usually what happened with me) so it shouldn't take too long