Phil,
That's really cool. You might try the gyro page (manual page 129) instead of Gyro gain settings using ATV. Set all ATVs back to 100%. Throw limit is set on the gyro pot. Zero to 100 clockwise for the GY431 if using digital servos. Gains are set on the gyro page. The Gyro page allows you to set the switch position, mode (rate or AVCS), and the amount of gain in a percentage. No worries about negative numbers for rate mode. Each switch position has settings for 3 gyros. This means you can have 3 switch positions and 3 different gyros settings for each switch position per flight condition.

If you want 20% gain in rate mode you dial in 20% rather than worrying about the negative throw directions.

50% and 85% gains in rate mode may likely send the Flash into uncontrollable oscillations or wing wag.
I recommend you set in-flight gains in normal/rate mode to no more than 20-30% until flight tested. A highly recommended practice is to use the flap switch to change the gains according to airspeed. Less gains for higher speeds.
10% flaps up high speed, 20% flaps T/O medium speed, 30% flaps landing slow speeds.

More info, especially for our JR brethren can be found on RCJetAddiction.com. Even for we lowly F-users, Dustin's videos are good setup info.

Chris