fpc accepts -glc, but will it work? Or does one need to do -gl -gc?

For the help screen, what does the <x> after the switch invocation actually mean? You have multiple -g, -a, -s and -i suboptions, but they are not indicated as -g<x>, -a<x>, -s<x> and -i<x>.

Also, how does one figure out from the help screen when bunching together suboptions (i.e. -CritoR) will work and when they won't?