The feet went together without a hitch, some minor filing and sanding to make the fiddly little pistons fit, but that was about it.
For now the feet are just attached with some florists wire (for legs and positioning). With the massive amount of weight of the upper body it sure needs some solid pinning though. It'll be a job best done with power tools once the 'hound is together.
(It feels a little like a cop-out using a prefab base. The battlescape is pretty nice though. And with a prefab base I can concentrate on getting the Warhound together. I know that once it's assembled I'd be itching to paint the titan instead of modelling an epic base for it.)