hey, got some questions, wondering if anyone can help. got a '74 sunn model that i just had retubed but am thinking about diffrent tubes already. right now i run it like this. sg>fd2>hot british>sunn>orange 2x12 with v30 and em tonker. anyway, my levels are set so i have a nice clean tone, step on the fulldrive for mild od, and tonebone for serious black dahlia murder crunch or machine head's burn my eyes crunch. anyway, messed with master volume blah blah blah, kinda dig the natural tube breakup, but it's not as smooth as the fd2, right now i have the mullard reissues, which are nice, don't get me wrong, but i'd like to have mild od from the amp and use the hot british to have as a heavy pedal. the 6550's are the gt's, i believe rated at 6 or so on their scale, will i need to switch them out or get the kt88's? can i just switch out the 12ax7's for smoother higher gain ones and leave the 6550's in it, and get close to the same sound. the sound i'm going for is along isis, pelican, insert other newer stoner/doom metal band cliche. haha. sorry about the long post, just wondering what people's thoughts are on some nice tubes. thanks.