I recently saw a video and couple of pics of a Draft/WB cross by Waterford (Hanoverian) - it was a 2 year old, and a lovely mover. It was a heavier type 2 year old, but well proportioned and light on its feet. I’m not sure I’d look for anything too light - you could end up with something huge bodied but too light in the bone - too divergent types don’t always make a nice “medium” offspring.
If she’s crossed well to Saddlebreds in the past, why not look for a nice, sport type Saddlebred? You know that cross works!
Edgar, here on COTH, has several Warmblood boys - you might ask him if he’s crossed any of his boys to a draft type horse…