Once you get to your wanted color with HQ4%/RA, do you think you could just use OTC HQ2% for maintenance everyday instead of the HQ4% 2-3 times a week? Or would that be ineffective in keeping your skin tone?
With someone who changed dark skin to light skin, the 2% would be all but useless. You'll need the 4% to maintain. As for how often, it varies from person to person so you'll have to gauge & assess what works for you. Slowly reduce use until you see no more lightening BUT no darkening either. 2-3x/week is a general guideline.