On Tuesday, June 4, 2019 at 4:28:00 PM UTC-7, Mike N. wrote:
I just insured with Costello through SSA.
It's about 10 percent or so more to bind coverage that allows others to use your glider.
They do require a CFIG cockpit checkout for the pilot using the glider prior to being flown.

Many times in the past I added someone to my insurance at NO cost. Just had to be a named pilot, not open ended, and have a cockpit sign off. Can be a good idea to add your favorite instructor or mentor.