A verification for adjusting wattage to sub

So the amp I'm getting is a 1200 watt amp constant from 1.5-4ohms and 14.4 or 12 volts. My subs can each take up to 500watts each. To adjust the gain with a volt meter I know you take the squar root of th power of amp in RMS multiplied by the resistance of speaker load. Adjusting the radio to max listenable volume and then adjusting the gain to the correct voltage is supposed to ensure that you won't go over the max wattage for the speakers.
If I were to input the max wattage RMS that I don't want to go over instead of the max wattage the amp can send out, would that effectively make my speakers safe from getting too much power? If I'm confusing in asking this let me know and I can try and reword it. Hopefully you all understand me though. Thank you in advance for any of your help.

 

Yes it should. Also several tables online to give you the DMM reading you need to match the gain to the max desired output. Also note that pumping a test tone through the system will probably give you a higher output reading then you will get with normal music as the test tone is constant while music notes are transient.

 

Two thoughts.

1. Why are you buying power you can't use?
2. Wouldn't it be easier to stop turning it up when you hear it begin to distort?

 

I'm going all out because of the quality and size of the amp. Also, I won't need to upgrade the amp later on if I get more powerful subs.
And adjusting the gain with the multimeter ill be able to gaurentee that it'll never overpower the sub. Just extra reassurance for me.its actually really easy to do with a multimeter