Woah!! thats a big burn out!!
I've not run colour subs of M42 in over a year now, since then, all my imaging of M42 has been in Ha, and with the 16bit depth of the CCD and the narrow bandwidth of the Ha filters I get about half that amount of blow out around the trap... That must have been a real mean mother to process down... and after having seen that 30min sub, I can say with certainty that you did a marvelous job of blending the 5min with the 30min subs... just needs some 1 min and some 20s subs to tone down that last little bit...
Keep at it mate!
This one will look great printed out... I still remember the quality of the print you showed me of Corona Australis through the np101, This should have a very similar quality to it in print!