I am not a big fan on weighted sit ups. I think if you do a leg lift you will work the lower abs that never get touched. It also hits the upper abs as well. I used to train heavy on this machine and my upper abs got to big. It looked like I was fat, big diaphram. The lower abs are the ones you want to develope. A true six pack is being lean enough to see your abs to begin with and having them developed. If you trained them real strict like you said then I can quarantee you are ok. Being lean with good abs and some half way decent shoulders are what the birds like. I mean girls.
