Congrats !!!
You've got one of the best metal amp ever made. This is going to take all its sense when you're going to play it with a band. It has a sick tone but what i like the most is the way it cuts through the mix, some other amps i have tried sounded as good or better when playing alone but could not compare in a live or studio application.
If you play heavy music you should experiment with EL34s. Many metal players i know tried El34s in their recto for rythm works and never went back to 6L6. Try SED EL34s and ask for "late break up", best power tubes i have tried in my 2 pre-500 Drs. I own #29C and 406D. I actually happen to like C more than D, i find it to be meaner yet more defined and focused at the same time. But this is just my taste i guess
I plan on selling my #406, i don't use it anymore since i have #29 wich i got from Epelectro on this board.
here are my rev D settings if you want to tried them:
(very heavy but thight and define rythm tone)
El34
bold and siliconne
loop active (nothing in it), send knob to 7
red channel
master 12 o'clock (control the amp's volume with the black knob on the left (loop's return))
presence 11 o'clock , bass 11 o'clock, mids 13 o'clock, highs 13 o'clock, gain 12 o'clock
now the icing on top of the cake
IN FRONT of the amp
put an Overdrive with Gain set to 0 (zero), tone to 50 to 70%, level to 60 to 90%. (best and also cheapest OD i have found to put in front of my Mesa to play Metal is MXR Zack Wyld signature OD)
now with that hot signal you will need to put a Boss NS2 (noïse gate) between the OD and the amp. Otherwise the amp is going to be uncontrollable. settings are thresold max, release min.
this is the formula i have come with after 8 years of testing and improving my tone with my 3 Drs. (i also own #11950 a 1998 2 channels)
These settings are the ones i use specifically with rev D and for rythm works.
For lead works i use different settings and the other channel.