I used the 1/4 track nuts from gzila
And your choice of 1/4-20 3/4 bolt. I used these
Use medium thread locker.
One note: the handles will need a little material removed in order to sit flush with the GFC t track. Which i recommend as it will be a lot stronger and less likely to damage the t track with weight. About an 1/8 inch from the inner diameter plastic hole, using a half inch cutting wheel on a Dremel. I’ll post a picture in the next post.