This is possible but not an easy task... I would rather try to reduce the value of snubber caps first. If that's not enough than replacing cathode bypass caps for something smaller or you could also try bright cap on the OD level pot...
just to give you few ideas
+1
I wouldnt convert a Non-HRM to a HRM, just because the OD may seem a litttle darker than the Clean. Try different tubes in position V2, before you perform any mods. E.g. a Electro Harmonic 12AX7 tend to be a bright tube, so you could try that.