Digital scale and level

[Andrew Sarangan <europaxs@usa.net>]

I am buying a few tools in prepartion for my Europa project. I have a couple
of questions, and I hope someone can answer.

Digital scale: what accuracy is required from a digital scale? I have seen
ranges from 0.001g to 2g accuracy. Walmart sells a digital kitchen scale for
$20 with a 2g accuracy. Is this good enough?

Digital level: What specs should I look for? Is this tool really neessary?
What's wrong with a carpenters spirit level? 

Thanks!!