Why don't you just go out and spend the few bucks on a sheet of eggcrate and try it before you take all the time, money, and effort you'll spend on making a mesh cover ?
With your small tank, one sheet of eggcrate/light diffusor will cover it for, what, >$20 ?
Give it a try
I love mine
I don't have any problem using that but people say that fishes can still jump through the holes. So many schools of thoughts just for one top
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You wouldn't want to see my tank. I don't use fancy equipment and I am a noob