AS for how you would actually going about basing the models I am unsure, as I don't know how you want the basing to look, or the the gravel etc. But something I find certainly helps is leaving the bases off of the models until its finished and use PVA to stick the models to bases (it works surprisingly well).
Me: To be honest im amazed there isn't a chaos god of not revising or at least chaos god of procrastination
MidnightSun: There will be, when enough people do it. Y'know when the Eldar were all engaging in their hedonism and Slaanesh ripped open the Eye of Terror with his creation? Slaanesh will have NOTHING on the God of Procrastination, and his vile minions will carve the galaxy asunder in a thousand year reign of blood.... Tomorrow