I too was having a problem with the speed ( Lack of ). The actuator takes 22 seconds @ 8V to the Robart power box. Robart told me the speed is not going to get any better !
I have recently replaced the linear actuator with a high Torque Digital servo, and programed the speed @ 2.5 seconds.
I have a Robart actuator for sale cheap !
My cycle time for the Robart retract tail gear is about the same as yours (23 secs) which is 4 or 5 seconds slower than my Robart Electric main gear. I guess I'll just live with the slow speeds and hope that I never need to lower the gear in an emergency requiring a faster gear down time. Another question I have is the delay between switch and the actual start of the retracts is about 3 or 4 seconds. I have the settings on the control box set to no delay, yet there is still a 3 or 4 second delay before the gear is activated?