Very Nice Jon! It looks like it was MADE for the Sammy. Just be sure the fan on the back of the Sammy has a couple of inches to breathe.
If you're happy with the sound of the 150 as it is, by all means leave it alone. However, if you feel something doesn't sound quite right, you might try mounting the 150 in the same space, but just a bit further forward, so the front edge of the 150 is sticking out of the enclosure by an inch or two. This would help minimize any reflections from the entertainment center itself. Should you do this, you also might pull the 60s out into the room a like amount, for the same reason.
Again, if everything sounds fine to you, feel free to completely disregard my ravings. Everybody else does.
I'm NOT a competent wood worker and much admire anyone who is. It really does look GOOD! Bravo!
