Russ, it looks crazy flimsy at first look. Knowing it's bolted to a rotisserie isn't real clear when first looking at it, and honestly that rotisserie doesn't look real strong either. But don't get mad at someone concerned about your safety. We have had some smart ars comments about safety lately that are a little dis-concerning. There is always room for talk on safety, and anyone who gives advice is thinking about nothing but the horrible thought of seeing a fellow forum pal being hurt.
Getting back to your question, there are control points all over the car, usually suspension mounting points are the best. But on that regard why do you need it perfectly level? Most of the time you want to measure things against the car it's self, not the earth. Let me put it this way, our $30K laser measuring system first measures where the body is in relation to the earth and then uses that info to tell you were all the points are related to each other.