I would say try doing at least 2,000 a day while focusing on that Chakra. Somewhere around the 500s I feel the Chakra get warm due to the seed sounds and focus I am placing on it. Around 2,000 will have a nice mind altering effect.
Though there was a day I did 20,000 recitations, I was so buzzed that I could not walk properly afterwards.
And also as Omni pointed out, the most important thing is to focus on the Chakra. Don’t beat yourself up if you find your mind wandering, but gently get back to your Chakra.