Height shouldn't be an issue since the risers range from 9 to 12 inches. As for depth, you will have some clearance in the back anyway for wires and ventillation. You would probably have the speaker a 1/2 inch in front so that would leave 2 1/2 inches in the back, which isn't a lot.
I have a Paradign c3 under a 10 inch Synergy riser and I'm pleased with the shound. It's a double with about 300 pounds of electronics and a CRT so it's pretty stable.
The one cautionary note I would say about Salamander is that from my experience their quality control has gone a bit backwards as has their quality - they've cut a few corners.