Britain's House of Commons has 646 members (it was 653 until the 2005 reorganization in Scotland that made Scottish constituencies equal to English ones and will be 654 after the next election), and the House of Lords is even larger. They never have a problem functioning.
Let's be honest. Very few members of the Lords attend. The quorum is 3. The Commons Chamber, IIRC, cannot hold all the members, IIRC.
In principle, I agree with a fixed population representative system. I note however that the PA State House has 203 members, and that has not improved representation.
