What is it with projects and 555 timers? Use something modern, please!
PWM and MOSFETs would be fine but you will have to drive the MOSFET gates quite hard. SCRs would also be fine, and probably easier to drive.
Either way, current feedback would be a good idea. You can use a hall effect current transducer to keep the nasty voltages away from your fingers.
You need a microcontroller to do all the control. I've worked on circuits that controlled DC motors, and used op-amps and discrete components to do the control. The boards were 400 mm square. In a microcontroller, all your timing an ramp functions can be done with no extra components, and all the extras that you haven't thought about now can be programmed not soldered.