I like the idea of using a lobotomized servo motor! Gives you control over speed and direction. It a lot simpler. If you need only partial travel of the jackscrew - while observing the reaction in flight a lobotomized servo is the way to go.

However there is a big drawback, there is no easy way to use end travel limits. If you use a NC switch to cut the power, it won't start up again. An advantage in using the DC motor and switches is a self completing cycle. This would be the way to go if you need a specific distance for the jack screw to travel each and every time.

In some aspect our transmitters are extremely primitive. You should be able to tell a servo how many turns to make. Then you wouldn't need to use limit switches!

John