NPD Santini Michelangelo LE

[ilikenails]

even for a formal italic just glides across the paper.

It's a very nice pen, but I don't think the nib is a "formal italic." From the picture of the nib and the writing sample I'd say that's a CURSIVE italic - which looking at the maker's nib page is one of their specialities : https://www.santini-italia.com/gold-nibs.html

...A cursive italic is halfway between a formal italic and a stub. Getting a CI as smooth as you report is impressive, combining it with semi-flex much more so! You really wouldn't want a formal italic - they're for slow, deliberate writing only - basically, calligraphy. (In fact, probably for that reason, Santini don't seem to make formal italics. They certainly could. They're a much easier nib to make than a cursive italic - calligraphers often make their own from regular nibs.)