Misty here's a Trisquel 7 Gnome shell :)
GNOME Shell uses 3D acceleration if available, software rendering otherwise:
https://fedoraproject.org/wiki/Features/Gnome_shell_software_rendering
GNOME Fall back certainly is lighter. That said, my wife uses GNOME Shell on
her laptop with 2 GB of RAM and does not seem to ever swap.
Two
I do not use Compiz. I have been using GNOME Shell since Trisquel 6 and it
may have additional dependencies for accessibility.
See the attached files for screenshots.
"Zoom" in the "Seeing" tab of the "Universal Access" (in the "System
Settings") has "Options". In particular, the magnifier does not have to be
full screen. It can take half of it (and you can choose which half). And it
can "Follow mouse cursor".
