I'm not an amp tech but I would think the whole power section would have to be changed, same with output transformer.
If you are looking for the "EL84 chime" consider EL84 driven Lunch Pail amps.
What do you don't like about Studio? I have a Studio 22+ and yes, I agree the Dyna-Watt give the amp more power, more headroom but loses the EL84 chime. I also find the gain a bit noisy when turning it up for some chunka, chunka metal sound (hint: Mini-Recto) and switching between channel, I never could get the loudness right between the two channel to my liking. So I thought about sell it.
But then I thought, "What about making it a dedicated low wattage moderate gain amp, Mark II(B) like-gain?"
So I changed the V1, V2 with a 5751, and 12AYA (yes, very low gain) preamp tubes. Not only did I get a moderate gain, but the switching between the two channels was more useable!
So perhaps give that a try if you are looking for moderate gain.