The Onlinestepper T6 Servos seem to be step & direction only, so you should be able to use the same control as you were using for your steppers.

Do's
Follow the instructions in the documentation for your servos.
Tuning instructions are in the documentation. Normally there is an auto-tune procedure.

Don'ts
Do not mechanically connect the motors to the ball screws until you are sure you have the servos under computer control and know what to expect.