Can anyone help with references for glide ratios for basic training gliders, Blanik, K13, Puchatek etc, with full brake or half brake deployed?

The internet is not very helpful for finding this information. A reference of 29 to 1 for a K6 -no brake and 7.1 full brake is about all I can find.

Given a Blanik at, say 28 to 1 no brake deployed, would around 8 to 1 full brake and say around 15 to one half brake sound about right?

Thanks in advance.