I've been f'ing around with my DRRI for a while...trying to get a mini-twin thing, kinda, basically more headroom/later breakup. After doing a bit of research here and there I found a few things that may help you.
1. Can't use 6l6's unless you upgrade transformer, choke, etc.
2. You can tame reverb with a 12au7 in reverb driver V3.
3. You can get more headroom with a 5751 in V2.
4. You can get more headroom with a weber copper cap rectifier.
I haven't changed the speaker yet, it sounds pretty good to me. I may pick up a used weber california.
And, Clip the bright cap.
There are mods to jump the two channels in phase and one for a mid pot.....haven't tried them.
I found a nice overview of mods (circuit and components/tubes and speakers), here:http://reitzel.com/schematics/Fender_Deluxe_Reverb_Reissue_Modifications.pdf
I'm running a Fulltone GT500 into it, using the boost and low distortion for a nice crunch when you dig in.
Overall, for smaller rooms, this amp does it. Ed.