Kia ora, Trevor. It is a bit curious for a couple of Antipodeans to be discussing a German / US glassmaker! I suggest the signature on your piece is indeed the same, and mine is also small, just a shade over 10cm.
The German / US Eisch glass factory could be a source, but they do seem from their websites to be a bit more production oriented. That indisuptable source Wikipedia says of Erwin Eisch's work:
Although many of Eisch's pieces of the 1960s and '70s was rooted in functional forms such as the vase, the bottle, the pitcher and the stein, the usefulness of these vessels was never Eisch's goal. "The purely plastic form, with glass as medium, was a means of art free of an end," he wrote.
Wiki continues: Eisch described his own glass forms of the sixties and seventies as "poetic or pictorial realism." He made clear that such a realism did not rely on observable fact, but on his inner reality; his fantasies. As important as his reliance on fantasy was to shaping his art, his unwillingness to compromise personal vision to appeal to the marketplace was just as vital. Therefore his early pitchers, vases and teapots are so eccentrically shaped as to seem to be in the process of becoming, rather than being, commonplace objects. Unique and imperfect as Eisch's forms are, it is not much of a step for their creator to anthropomorphize them. Eisch said, "From a glowing inert mass must emerge things of beauty that are endowed with speech. A talent of innovating, creating animatedly, and the breath to blow are requisites. Without blowing nothing happens."
That seems a bit grandiose for my little bottle, which is also later than the period they are talking about. But there must be people on this Board who know more than I (or you, with respect) about this, even if they may be asleep at present. Here's hoping for some enlightenment.