We managed both a small and a medium sized game in less than three and half hours, which is without having played the game before and so I it felt it was fairly speedy overall, all things considered. That time included making a couple of cups of tea and stopping to have discussions about whether or not certain things worked to create a satisfying game-play feel, so ultimately probably closer to three hours or less in total for the two games played.
Brummie was really supportive and kindly gave feedback and insights, as well as noting the log of changes to be made and also took two of the pictures in this post (thanks very much mate!).
Anyway, suffice to say, it feels on the right track of what I want and I hope to get more Squad Wars gaming in with Joes versus Cobra before too long.