It depends on the light source and the coral. Nearly all acropora will thrive with growth at up to 750 PAR under MH and T5, but will not under LED. They can do ever more with daylight spectrum like 6500k.
Color can be different than growth. I keep my dragons (CITR Red, Purple Dragon Eyes, etc.) at about 350-400 because the color is better than if under 750+, but the growth is the same. Millepora, tables, efflo all have better color with more output.
I do not keep MBP&S, so no idea about that part of the mixed reef.
LPS start to slow down at 500 PAR at my house... I would keep them under 350 if you can. Keep the LPS at the bottom and you will be OK... remember that most euphyllia are collected in waist deep water and can handle the daylight sun spectrum in massive amounts.
Softies just continue to grow. I grow jawbreaker and bounce mushrooms with the same light as the SPS since it grows them faster.
Clams, which are the best part of a mixed reef, IMO, will benefit from all the light that you can give them. I start them off under 6500K MH at 750-1000 PAR until they grow. Once acclimated, they thrive under this much light and quickly put on new shell. You cannot give them too much light.
Lastly, keep in mind that PAR meter does not capture all of the spectrum that coral need... it can vastly underestimate some light sources and without know the type of light and spectrum, meter type, sensor type and if it was in or out of the water, you can have readings that differ from each other 100%. For example, my Apogee 510 already corrects for being underwater and does a better job with blues, but it forsakes spectrum over about 660 and below about 440 on a pretty steep line... so a LED with 350 PAR will be significantly less light than a MH or T5 reading the same 350 PAR since the LED does not have any helpful far-red and not as much helpful UV and violet as the other types.