What size push bail will fit around a Swarovski cosmic ring? I am using the bail to connect jumprings and other links to the ring.
Choose a push bail (sometimes referred to as an ice-pick bail) which is longer than it is wide. That is to say, the length from the bottom where the picks are to the top where the arc is would be longer than from side to side. This allows room for the length and width of the ring at the point it sits in the bail. A good rule of thumb is to select a bail length that is about 2 times the length of the ring's length. So if you measure from the inside arc of the ring to the outside arc and get 7mm, select a bail that is 14mm in length.
A good alternative would be donut bails that are made more specifically for this type of focal piece, accounting for the width and length of a ring-type focal piece as well as a donut. There are a variety of choices; select the one that fits your overall design.