I have the 360 if this is the process lens. Does it have the filter slot
in the barrel? Should be quite a bit of info on google groups about these
lenses.

 Does it look something like this?
 
 http://homepage2.nifty.com/akiyanroom/redbook-e/apo/apo455.html
 
 I think the coverage depends on use. Should be a bigger circle of light
then what is considered the coverage. The number given in the above link is
likely for 1:1 at high quality.

      Nick