Installing dance floor in marquee

[ukpartydj]

I've been asked to provide a 20x20ft starlit dance floor for a marquee, I've only just bought a starlok and outlok floor (so limited experience) observed my starlok floor has tight joints and my wood effect outdoor one is more flexible. I wouldn't think twice about installing the wood effect one in a marquee as I've seen the same "outlok" floor installed on very uneven ground with no real issues.

Have any of you dance floor suppliers installed one in a marquee before?
Do you need to lay a damp proof membrane underneath?
Does the ground need to be DEAD level?

[surround sounds]

We put led dancefloors down all the time in marquees without any problems although I would take some square carpet tiles with you just in case the floor is uneven