+1 on the 8FG!!
The fact that you already have some R617FS receivers is a very good reason to go with the 8FG, since they will not work with the T8J. FASST compatible receivers from FrSky have a good reputation and are very attractively priced as an alternative to the Futaba models.
http://www.alofthobbies.com/radio-ge...ompatible.html
Best of luck,
Pete