Hi
I am a college student and I was given a project to sketch a tanning bed I was wondering if you can help me by answering a few questions.

First I wanted to know what would be the optimal distance between the legs so an 100 kg person could lay on the bed without risk of him breaking the joints?

Second what material should the bed be made of so it would light and have a long life in humid conditions?

Last what is the best way to sketch a vertical axis?