Nice setup!
The first thing I would do to get that kind of tone is swap out any 12AX7s in the preamp stage with NOS 5751s. That is instant 80s metal tone, especially if you have a high gain amp. You might also wanna swap the JJs for Mullard or Tungsols. If you have the room for it, you might wanna look into 6CA7s instead of EL34s altogether. Putting an OD in front of the amp, even if it is high gain, will go a long way to getting that tone, too. Just make sure you back off on the preamp gain. You might even wanna just boost the clean channel. Finally, put a BOSS GE-7 in the FX loop for a solo boost, set for a small mid boost.
If you have a decent cab already, you might not need to go any further than that. Yes, the Scumbacks will most definitely improve your tone, but I wouldn't put them on the "must have" list for Lynch/DeMartini/EVH type of thing.
Hope this helps.