At least one company (Groove Tubes is the one that's famous for this) relabels and resells other companies' tubes with a bias rating that they claim lets you not re-bias as long as you use the same specific type and rating. Never tried them, can't say how tight of tolerances their ratings are. Other companies (like
www.tubesandmore.com and
www.thetubestore.com) match sets of tubes themselves without re-branding them, which is what I prefer. I never use the same type of tubes twice in a row though, there's so many good tubes out there that I want to try all of them. But if you find something you like you can always buy a matched set of 4 or 6 or 8 or whatever
The Turnip Greens looks like a cool pedal, Klon clones are everywhere for a good reason. I'm willing to bet the HT Boost isn't going to do work anywhere near as well for the SC-X2 as it will for your Blues Jr. There's a ton of solid state circuitry in the SC-X2, and a huge clean signal from the HT Boost probably will overload something in a way that doesn't sound good. Probably. Or maybe running it with a really low boost setting will help the SC-X2 preamp voicings sound more authentic, since the Blackstar is all tube. There's only one way to find out.
I personally use a Black Forest pedal for a big clean boost.
And 10" speakers are something I'd love to try more of, but can't really justify spending the money to try every 10" myself right now. I have a '59 Bassman reissue with 4 super cheap Celestian 10"s that I'm not happy with. But I prefer my 8" Orange speakers for practice at home and a 4x12" for being loud, so the 4x10" is gonna keep being a red-headed stepchild for a while.