From an installer perspective, here's my advice.
No one is going up on that roof with that pitch, so don't count on it being any higher than the eave. Also, few techs carry anything larger than a 28' ladder so don't intend on any location where a tech can't safely get to with a 28' ladder. Otherwise, any service appointments might go through multiple reschedules while you wait for someone with a longer ladder.
I would hate to see you destroy that red brick by drilling into it. I also think you might want to try and keep the shell of your home intact so I recommend a pole mount. They are the easiest to service in case you get snow or ice on it, or if a part needs replacement or if they upgrade the dish itself.
In any case, put the prewires near the electrical panel so the tech can ground your system. If you don't want it there, then make sure to have your electrician install a #10 ground wire to that prewire location. Place 5 coax wires for good measure there as well. You can plumb for a pole mount by installing an enclosure or access panel and putting the house wires there and then have your electrician run a 1.5" non-metallic conduit from that enclosure to where you want the pole mount to go. Have him leave about 6 inches of it above the ground cover. Have the electrician put a pull-string in the conduit. You could hire a local fence contractor to put up a 1 5/8" fence pipe. Make sure its level all directions and that there's a clamp or something attached to the pipe in the concrete to prevent it twisting in the wind.
Finally, you can contact a local satellite retailer and hire him to do a site survey about a week before your electrical rough-in work is set to start. He can make sure you have a good location. Expect to pay for him to survey the site. He might be willing to come out and do it gratis if you commit to becoming a customer and he can handle it during a sales visit. Any location should give you as much of the "arc" across the southern sky to permit for the widest range of services.
