Without drywall up, you're not going to know 'where they sound best' unfortunately.
Plan your seating to put you in a good place acoustically, avoid 1/2 of the room length and room width and try to keep away from walls beside and behind at least 2' - more is better.
Side surrounds will go (assuming dipole/bipole) directly to the side of the seats if 1 row, between the rows if 2 rows. Put them up 6-6.5' off the floor.
Lay out your screen size and plan the speakers to clear that side to side and still stay away from the side walls and close to the screen as much as possible. Speakers should be between ear height and 1/2 up the screen.
Once you get the drywall in (assuming not inwall fronts) - tweak speaker and sub location to get the smoothest response at the majority and most often used seats. If you have a choice in the bottom octaves, shoot for peaks rather than dips in response (peaks can be EQ'd out). Do all of this prior to any treatments in the room. Once you treat it, if they're doing their job, they'll mask potential issues.
Also, if you do it this way, you'll have a better idea of where the FR issues are coming from and what's causing them so you'll have a better idea of how to more effectively treat the room to minimize them.
Bryan
