Just a few thoughts in general about handwriting, my 2 cents, for what it's worth.
To me it would seem like someone such as the Zodiac Killer, knowing his handwriting is under intense scrutiny, might exclusively use print handwriting for all his Z correspondences and exclusively use cursive at all other times (filliing out forms, wriiting personal letters and notes etc.) i would lean towards this theory considering that nowhere does Zodiac use script print. Nowhere.
I think Zodiac would have been too smart to try and use hand print for his day-to-day, personal handwriting purposes. I dunno if its just me, but I get the feeling Zodiac might have intentionally went out of his way to never leave behind a trail of handwriting in print form other than his Zodiac correspondence -- and perhaps used a flamboyant trype of script, to just completely differentiate it from Zodiac's often chicken-scratch.
Not being a handwriting expert, maybe someone can shed some light on a question that comes to my mind. If an analyst has two samples of a person's handwriting, one in print and one in script, is there a way that they can determine that the handwriting came from the same person?
For example, below is my own handwriting in both styles:
Would an expert be able to tell, on a letter-by-letter basis, that I wrote both phrases?
Since most everyone's focus is on the Zodiac's print writing. it would be very interesting to compare different POI's cursive handwriting samples (if they were available), just to see what might be gleaned from them.