Not everything that they sell is accessible without an email question.
They are good about answering direct questions, and will read notes that come with an order.
Be sure that "membrane" refers to mylar sheets with traces printed on them, and "blanket" refers to the rubber sheet that lies against the metal plate.
And yes, I think that the current thin white latex sheets feel more responsive than the old thick black rubber ones.
PS - apparently, a "spacebar" is not a "button"