Ok..
1. I don't know what the clearance is with a Nexstar 11 but the field derotator juts out the back a fair way. Maybe one of the Meade users can answer this. I do know though the the derotator doesn't work on all areas of the sky.
go figure
I'll try to dig up the web link for that info.
2. As long as you can see down to about 20 -25 deg either east or west and see straight up then you can polar align using the drift method. You can do it higher east or west but it takes a little bit longer and you have to swing back and forwards from meridian to horizon a few times using smaller adjustments. Nothing that couldn't be gotten used to. Nearly polar aligned will always be better than alt/az. You can still get field rotation in equatorial mountings. It depends on how far from polar alignment you are and how far the star you are trying to guide on is away from the area you are trying to image. The closer the better.
You could also align using the 300D method. Ccheck out Alex's (xelasnave) method here
http://www.iceinspace.com.au/forum/s...ad.php?t=11654