If I have 100 amps of non-continious load and 150 amps of continuious load.

100 amps + (150 amps x 1.25) = 287.5 amps. OCPD selected = 300 amp. as permitted by 240.(B).

My question is since this is prior to adjustment and correction factors. If i have to increase the size of the wire because there are 6 wires in the conduit and a temperature of 40 degrees C. I beleive I would have to use a 500 kcmil conductor. Do I have to increase the size of the overcurrent device or is the 300 amp. OCPD Protecting the 500 kcmil wire?

500 kcmil- 90 degree column =430 x .8 x .91 = 349.44 amps