Bill:
It is OK to use one of the airplane CFI FIRCs ( I've used American Flyers with reasonable satisfaction). BUT if you would like to come to New England for a few days there is a glider specific program at Springfield Vermont in September. See below from Bill Stinson (designated examiner) . ROY

We are on count down for our forth CFIG instructors camp at Springfield. I hope all of you have had a great summer and flew a lot teaching and staying current. So this is just a reminder that you are all welcome to join us at Springfield on Monday September 11 at 8am for registration or 9am for the beginning of this years school. As usual to make this work we need YOU, SGS2-33 aircraft and we will provide the tow services of Walter Striedieck. Again the dates are Sept 11 through Sept 15. We still have openings and if you know of someone who would like to attend if they Google Soar Vermont they will find the camp info and registration, or just have them show up on Sept 11. Any questions will be answered by me at 802-496-3450. Hope to see you on the 11th. Bill