Dunno, but I think it might be a bit more power efficient to use the 128MB variety? I lost PMs in progress twice to @trag about this stuff. I think I'm just going to start a parallel thread about the move to 72-pin in a relatively stock SE/30replacement board. I have a single, angled 72-pin Socket. I think more headroom might be necessary for the SE/30 case than the straight up variety might require?
Not to rain on your parade, but IIRC no Quadra could address more than 256MB? But maybe they can! Given original "supported" configs at time of release and the introduction of higher capacity modules using higher density RAM ICs, you never know until you try.