Honestly, yeah. A pedal would make a lot more difference than swapping tubes.
But tube rolling is also fun.
Personally, my preferred preamp cocktail is a Sovtek LPS in the PI, and all Chinese in all other positions, LOL. But if you want a bit more liveliness, pick attack, and responsiveness, I recommend the Tung Sol 12AX7 in V1. I generally prefer Russian tubes in the power section, as I prefer their sonic signature there. Particularly, EHX or Sovteks, but I do like bright, tight, agressive, and open power tubes, personally.
But keep in mind, the difference is not going to be night and day either. You don't swap tubes to transform an amp. You swap tubes to fine-tune an amp that you already like.
I've never experimented with lower gain tubes in my amps. People sometimes use 5751's or 12AT7's to lower the gain of certain amps. I've honestly never considered doing that. If you want less gain, just lower your gain, LOL. There is also an impedance (or resistance, forget the right term here) mismatch by swapping some tube types, so the amp is obviously not going to behave as designed if it was meant for 12AX7's.
People mention it makes their amps have more "headroom" this way, but not really. Headroom is how loud something can go without distorting. You're certainly not going to add any more volume to an amp this way. Just less gain.