euro brace questions

[lockrookie]

question numero one:

how wide should glass be as to reduce flex on a 6x2x2 tank

question numero 2

if i take 2-2x2 foot pane's of glass and cut a hole in the middle putting each on each end of tank with a chunk between the two on front pane would that be enough to stop the tank from flexing.

i wish to rid myself of the center brace and have a centre overflow with keeping all plumbing working from the middle if possible.