Hello Everyone!

I have a bit of a dilemma I could use some help with. I recently discovered that my favorite Twin has two dead tubes, one broke when it fell out of it's socket during a move, the one next to it either has a short or it leaks according to my tube tester. Obviously, I need to re-tube it. Here's where my dilemma comes in:
This amp was already re-tubed with Groove Tubes H5 6L6's, and GT preamp tubes. It's had a killer tone for years and has always been the subject of questions by other Twin owners about why mine sounded so much better than theirs. Of course, it was the tubes. Now that Groove Tubes is no longer owned by Aspen Pittman, the tube grading system no longer seems to be in effect.
Since I cannot find 6L6's with the H5 power level from GT I need to find a match quartet in this power range elsewhere.
Would anyone know where I can find tubes that might be able to use this reference to match them?

Just for reference sake, what these tubes did for this amp was raise the amount of clean headroom and increased harmonics before the amp would begin to distort. Where the average Twin would be at full clean volume at "4" on the volume knob, and begin to break up as you turned it up more, this amp would still be clean with the volume knob on "6" but it would be louder than Boeing 747 with crazy harmonics and would begin breaking up as you turned up to "7."

I would love to get it back in that condition again, the key is to find the right tubes for it.

Does anyone know how I can use that reference point to compare with the tubes made these days? Or, can anyone refer me to someone who can use that kind of reference to find the right tubes?

Thanks in advance!

Harley