I might be able to dig up my palladium Maracross 2 manuals if you like.

Doesn't matter what  striker_saberwolf says, this fighter still kicks ass.

I loved Macross II. :3

The Metal Siren was most assuredly a prototype. You'll likely, though, continue to have trouble finding much information pertaining to it except that which has been altered and compiled purely for Palladium Books' Macross II sourcebook. The series itself is now considered not merely unofficial and non-canon, but seems to have garnered an effort by its' creators to "sweep it under the rug" so to speak. It is not brought up now spoken of in any way.