Use just the 600HPS, it will shit on any LED when it comes to growth, yield and flower production.
Beware of heat issues and hanging height room though, as an HPS light will need to be further away than LED lights.
3x3 tent is 9 square ft. Both lights together would be alot for that space. 600 watt light is more powerful. Led light 200 watts is equal to 400 watts of hps. The hps light will give you over 60 watts per square foot. Thats a good amount. There's only so much light a plant can absorb without adding carbon dioxide.