Just bought a pair of Elite rosewood grips for my 228,can anyone tell me which screws to use. I need slightly longer screws.

I'm fairly certain the P229 shares the same grip screws as the P228. So, you'll need P239 grip screws (which are slightly longer) in whatever style you prefer.

Check out TOP GUN SUPPLY for a wide selection of grip screws. They even suggest that change.

GREG COTE, LLC also stocks grip screws. Both are regularly contributing vendors here.

Yep the 239 screws are what you need.
Be sure to feel inside the magwell before inserting a mag as I have had a set that the 239 screws were to long for and had to pick up some washers at Lowes to bring the screws out a bit to keep from rubbing the mags.