I need to record one or two spoken voices, perhaps simultaneously, and get a clear/dry recording. I'm trying to figure out what I would need to do to treat a room the following size, with the following characteristics:

11.5'x10.5x10'. 3 doors, 1 window and 1 heating radiator. Stucco walls and carpeting.

What kind of treatment would I need? How much would I need? Where should I place it? Any idea of costs? Should I buy professionally made treatment, or would OC 703/705 or something else cheaper do the job?

I've also got the option of a slightly larger room (12'x15'10'), also with carpeting, stucco walls, 1 heating radiator and 3 doors, but it also has 3 windows (2 facing a somewhat busy street that can be heard). The top 3 feet of the ceiling are also arched.

Thanks in advance for your input!