Given it’s a 68, probably keep it stock and sell it. It is a great sounding amp, just not a huge fan of the raspy high end they tend to have. I prefer the slightly smoother high end in the Suhr/Friedman/Cameron/Hopkins stuff.
Modding those classics always reminds of putting goofy, selfrotating chrome wheels on a nice oldtimer car.
So many options with amps out there that can give you the tones you want and even more. It’s not the 80ies anymore when you basically had to choose from maybe 3 amp companies and then go with personal mods