Creating a landscape in Maya; using a polygon plane and the sculpt tool

I've checked that the footage I shot at Glenshee at the weekend is suitable, both from a script and technical point of view...and it is.

I'm following the tutorial below (Stathis, what a star, sent me the link) and am recreating the snowy hill using a polygon plane and the sculpting tools in Maya....and a still from the footage, imported as an image plane for reference...