Port Modulation File Format

I am trying to use a PORTMOD type of port and don't know if the formatting is correct.  The MWO Element Catalog is of little help because most of the topics are poorly written and obviously missing key details that would answer some questions.

I have a large modulation file that is Real - Imaginary pairs but it is unclear what type of PORTxxx will run this file.  There are parts of various descriptions of complex signal files (SRC_C) that imply that with the correct headers [(Re) (Im)] MWO knows how to interpret them but I have no idea if it works because my simulation has Zero Progress.  Nowhere can I find what type of port I can use for Re Im modulation files.  There are IQ ports and Mag(dBm) Ang ports

Another confusion is what should be put into the SPECTRUM = < >.  My file is symmetrical about the carrier, and I have found nothing that tells me what to specify.  There is a specifier DOUBLE_SIDED to use if the file is one-sided and another CONJ_SYM that will give the right side of a symmetric file.  But I find nothing to specify my symmetric file which I want both sides to appear in the spectrum plot.  If I omit a SPECTRUM = header the simulation fails.

Is there somewhere that describes all of the PORTMOD types and how to format them so that they run without days of trying things that don't work over and over again.  Also, is there a limit to the size of file that can be run?  Some places imply that 1024 points are the limit but that makes no sense to me.