I just want to say that sounds truly amazing, Good on you! Not that it sounds like you need any more encouragement that you have already gained from your results! Between you and Freakwitch, these are transformation stories that would do any over-hyped fad diet justice, except it isn't a fad and is eminently sustainable. Take a bow! (you too Reinhard!)
If you have had back problems, go easy on the Shovelglove, nobody wants a disc injury or sciatic problem. Having said that, I don't think there is anything better for your back, stomach and posture than Shovelglove. It is upright, it trains the back and stomach muscles as a single functional unit and it real-world movement that you will use carrying real-life objects or even your own bodyweight. I wouldn't bother with sit-ups, pilates etc because these usually isolate the stomach muscles, rather than training them in concert with your back muscles; as well as being done mostly lying down, which isn't very functional (except sometimes

)! Shovelglove is better, just start off with a 6-pounder (or 4 pounder if such a thing exists) and go carefully. Maybe stick with the running a while longer to give the back and stomach some general conditioning, then shovelglove-it-up, you won't regret it!
Congratulation, post photos for the shock and awe effect.
Phil.