I bought FoCal regular version and used it recently on my Nikon D610 and a few lenses, I am pleased with the results.
First, for my zoom lens (Tamron 24-70mm f/2.8), I can perform the calibration at any focal length, not just at the extreme ends. I think there may have been a warning about calibrating midway through the focal length range but it performed it happily.
As for light, if you have a flash gun then you can mount that on the camera, which will help with the target illumination. I got no warnings etc. that this was not a good idea (FoCal generally tells you if it's unhappy about something) and the flash fired every time. I got no warnings about target illumination when using the flash and I did without.