A bare 1200 probably runs below 25W.
Accelerators vary somewhat (maybe 10-40W).
HDDs power depends on size, RPM, generation, but not much more than 20W (startup) for 1.6" thick 3.5" drives (5.25" may go up to 50W!). Modern 3.5" 5400 RPM are <10W.
Optical drives ~10W.
Most probably you won't exceed 150W, but you need to make sure the 5V rail is strong enough for mainboard, accelerator and ~25% of the drives.
