Hey Paul, it doesn't look like you will have any problems. If you have significantly more toe overhang than heel overhang (which is common/expected for size 10 boots in a medium binding), I would recommend you move your bindings one notch back towards the heel edge. In the image I removed (sorry, image was too big and breaks the page), you will notice you have a good amount of clearance, meaning it will take a lot of angle to make your boots actually dig into the snow. I highly doubt you will have any problems with your setup, size 10 on a 249 waist width is ok.
Do you know what stance you use (angles, width)? This will also effect how much overhang you have.
You should also rotate your highbacks so they are parallel with the heel edge. Check out this article for more info on stance and setup:
http://www.boardworld.com.au/snow/content/category/stance-and-snowboard-setup/
In regards to images, at the moment we can't have images wider than 800 pixels as it breaks the page. We are working on a fix for this to automatically resize images greater than 800 pixels wide, but it's not ready yet. Feel free to repost those images at a smaller size.
Ohh and welcome to Boardworld!
