Fixitt - Roscal has said yes - if you can't create what he needs, my offer to help stands.
On the top issue - notice my conditionals (wall height, thickness, and thermal bond - also influenced by thermal conductivity of the block).
JD - two ways around your problem, one would require a little ingenuity.
Take the block itself and rotate it in relationship to the end mill's axis in your vice to create the angle (the ingenuity part). Just rotate the pic I made so the end mill is vertical to see what I mean
You could also add some bottom channel features by using the endmill sort of like a drill - making
small circular depressions in the bottom, overlapped at different heights, and irregularly spaced.