Take a look at the co-pilot from FMAdirect.com
https://www.fmadirect.com/site/fma.htm?body=Store
On the above link click on Co-pilot Part Number: CPD4
It costs $99 down from $119 or $129. Been out for over 2 years.
After a dozen flights using a buddy box, and never having been allowed by the instructors to land.
I bought the Co-Pilot and went out on my own, I did every thing fine. It was a big help.
Just like the flight tests of Co-Pilot I put the plane in an intentional roll pointing straight down to the ground and I removed my hands from the sticks of the transmitter. The plane became level in less than a second, well may be a second.
Every time the plane comes towards me, if I get confused I just let go of the sticks, breath, re think what I'm doing and take over again but with the plane already in level flight.
This thing works.
With a six channel you can use a channel to turn it on/off if you want to.
If your extra channel has a rotating knob on it (may need 7 or more ch. to get the knob), you can even control the aggressiveness (for lack of better word). But you don't even need an extra channel.
It weights 1 ounce.
Under their support link, if you read all the way down to the bottom, you can find some copies of the flight tests done by different magazines.
Good luck, by the way I don't work for them, I'm just a VERY satisfied customer.