The quick answer is 19 gauge and smaller (just remembering the quirky rules of wire gauges - bigger number, smaller the wire. But for clarity, we wrote a blog article on this. Most of the Murano Glass beads are a nominal 1mm hole.
If you want to use beading wire, .019 is perfect. You can use .024 on larger beads.
For a chart read our blog.
https://www.venetianbeadshop.com/Wire-Gauges-Bead-Holes_b_177.html