Stu,
Not sure what's going on on your side. I can't check the process without actually wasting some paper which I don't want to do now. I assume you have the latest version of APS and are using the latest Z3100 firmware which allows the APS to print on multiple sheets. If you do not have the latest firmware, I can see APS graying out the choices because the paper is too small for a single sheet profile.
If memory serves, once you load the new paper that you want to profile (81/2 x 11 is fine here) the printer will want to do a calibration first. Then it will prompt you to load another sheet (at least 11x17). Once the paper is loaded, you should have the options you report as grayed out. I choose the largest target to print and select "optimize for paper width" and it's off to the races.
Hope this helps a little...
Jim
www.jimcolephoto.com