63 and 442 with Wolff springs made a great improvement. Don't touch the engagement surfaces but polish the sides of everything that moves or slides...
Listen to PapaG.
I hesitate to reduce the coil mainspring in J guns, and especially .22 rfs.
The rebound slide spring is where you can make improvements. I've an assortment of Wolf springs, in weights from 11 to 15 pounds.
After polishing the rebound slide (be gentle with the current, Teflon coated MIM ones; the coating is pretty slippery), and where the slide runs, in the frame as well as the sideplate. The hand needs a polish too; use fine, India stones for everything.
It helps to attend to the ratchets as well, but I usually avoid that, for fear of losing timing.
I'll often use a 12 lb spring, but will drop down to an 11. Test hop it; does the trigger
always come back, even if released slowly? If not, go up a pound.
I'm usually concerned about DA, especially since I like Centennials.
In some ways, the older, forged parts give a somewhat crisper feel, but the new, MIM stuff works pretty well.
When you're done, check you haven't created a 'push off' problem with your changes in single action, and, again make sure the trigger always comes back smoothly.
I mark what weight spring installed under the grips with permanent marker, in case it acts up later. It is really hard to establish the weight of an unknown spring.
Moon