I've done it by sawing a kerf down into the limb tip 12" or so, and then glue in a tapered or parallel lam. I've done it at the same time I do the main glue-up on backed bows, in order to get the outer limbs to bend farther without breaking... and I've done it on selfbows to reflex or recurve the tips. Same effect as heating and bending, but less likely for 'working' recurves to pull out with use. Want the outer limb to work more? insert a parallel. Want it to work less? insert a taper. Static? Glue in a more drastic taper.
It's also a nice way to move the tips back forward again on a bow that took some set, making it more efficient, and gives it a nice profile too.
My favorite bandsaw blade cuts a kerf that a .050" lam fills perfectly... so that's how thick I make the taper on the thin end.