I certainly take 55.5's point on s t r u n g out shots on board and have hopefully learnt quite a bit from this exercise. Also how important it is to make sure the camera is carefully levelled up.

Rik, yes, there are a mix of speeds to try and avoid the 'clockwork mouse' effect.
From what I've observed, Roundhouse locos appear to be capable of better slow running than the generic Accucraft ones. Naturally, geared Regners are also capable slow runners too. ( Just my opinion; others may have a different view as I do not own a Roundhouse loco.)
Dave