Gregg, are you planning on having the C11 with the APO piggybacked?
The EQ6 (or Atlas) is a great mount for the money.
It is rated for 40#, so it should handle your scopes well, but if you are headed for Astrophotography, might want to rethink your strategy a bit. IMHO, the is no such thing as OVERKILL when it comes to mounts for Astrophotography, as you'll want a ROCK STEADY platform for your scopes, since any wind/movement will be transferred to the pic, ruining it.
I would say that you should rate your scopes to 1/2 to 3/4 of what the mount is rated for, and you'll have a great combination... anything higher than that as you'll be fine for Visual use, but might not be the perfect combination for long exposure photography.
The scopes I use for AP are (combined+rings) less than half of what the mount can handle..., providing a ROCK SOLID platform.
Of course, this is just MHO, so please take it "with a grain of salt"...

Clear skies! 8)