Bus - easy peasy.
I use aluminum as it holds its shape better. It WILL poke the daylights out of your fingers when you've cut it obviously.
The craft plaster strips can be purchased at Walmart, Michaels, Hobby Lobby, etc. It is simply gauze like material that is pre-plastered and you dip it into water. They make multiple widths. Woodland scenic also makes a similar product.
Sculptamold can be heavy when put on thickly, but I did the strips and then smeared instead of coating the screen with 1/2" like last time.
Anything that flexes WILL crack for the most part. However, if the table is sturdy (even if it tilts) you'll probably be ok.
Let me know how it turns out!