Coroplast thickness of coroplast?

Most people use the 4mm thickness. But it really doesn't matter -- it's mainly there for a moisture barrier and to keep the bedding from being kicked out.

Where do you get used election signs? I would love to get my hands on some...

Around here, you can pick them up off the side of the road now that the election is over. But you can also call the local headquarters of any political parties in your area and ask if they've got old signs you can have. Or check with sign shops to see if they've got some misprinted ones that they'll give away. This is the week for old political signs, since the election was just Tuesday.

We're having a municipal election on the 19th and it just happens that my housemate works for one of the parties

Although I do like the idea of the thicker, sturdier coroplast... I guess the fact that they're in the grids makes it sturdy enough? *frets*