The way spaces filled up around me last year by Thursday ( and I was on the second to outer ring Monday night...out in the boondocks at the time) the trick might be to have as few vehicles as possible to try to hold spots for. No particular guidelines on claimed space that I know of...others??
Burning Man 2003-14; Desert Carillon, HypnoHorse, Ulaume's Chimes, Iron Native, Black Rock Solar, Portal Collective, Center Camp Café Stage and Sound Tech
Keru's Phenomenal Phantasmagoria of Terrors and Delights