Don't cheap out on the charge controller. Spend the money on something that is proven. If you want PWM then look at Trimetric....
SC-2030 Solar Charger — 30 Amps Max- 12 or 24V PWM type - Bogart Engineering
If you want to go with MPPT I would get Morningstar.
Or go cheap and add an extra panel to the roof to make up for what you are loosing in the charge controller.
Whatever you get make sure the charge voltages are user adjustable so that you can program it for your specific battery. Not just generic lead acid or AGM settings.