There are a few cruise control options for the F6B. Since I just purchased my F6 yesterday, I'm researching accessories right now and know I will need some form of throttle lock for the long hauls. For now, I'm using the "Go Cruise," which is sold on eBay or their main website for $20. I used this on my FJR...you would need to purchase the sport version as the grips are thinner than a cruiser grip.

The other option is a Throttlemister, which I have not experienced.

And the other is Kaoko...I used their throttle lock for my FJR, and really like it. It matched the opposite grip end so I only had to purchase the throttle lock...not another end piece to match the throttle lock. Also, the Kaoko has groves on the end so you can easily apply the lock to the throttle. While activated, you can still easily adjust your throttle up or down on the fly. These run about $100-150.