Plexiglass Lid

[kit]

Hey All, i'm thinking of buying a sheet of acrylic/ plexiglass to cover the top of my tank. I figure it will costs less then a new hood. Rough dimensions are 48 inches wide by 18inches long.

Any suggestions on how to design it?

-Is it better to use 2 pieces that run vertical (24"x18) or horizontal (48"x9")?

-where is the filter best located? Middle or one side of the tank/and heater on the other side?

-What thickness of plexiglass should I use too?

Any tips would be also appreciated.