Re: [EE]: Synchronising 4 Linear Actuators with 4 x Op Amps and 6 MOSFETS

Reverse polarity mode

And the 324's slow output slew rate, combined with mechanical slop/lag, may
cause the system to "cook itself" as you get close to the setpoint.

18V will make it behave batter.

Now that I think about it, you may wish to consider using a comparator to
avoid the slow slew rate issues.

A window comparator providing a deadband to remove power within ~%5 of the
setpoint might be something to consider.