Visit any body shop with your colour code and ask them to mix you a sample in a small tub... Nominal cost to do this, you will also need some clear lacquer.
The day before you spray the stone chips clean them thoroughly with a cotton bud and iso propyl alchohol, to remove and dirt and left over polish and wax that has attached to the edges of the chip.
Use Cataloy stone chip knifing putty with a plastic spatula card to fill in the recess of stone chip only and make sure that it is as thin as possible but level with the good paint surface.
I use a hairdryer at this stage to harden it up as much as possible before leaving it overnight to go off... It can take up to 24 hours.
1600 grit wet and dry paper to key lightly the immediate area around the stonechip repair and to flatten the filler around a 2 pence piece size maximum... Don't go crazy, just a few light sands will do, check and do it again until you have an even, smooth surface... The better the finish at this stage, the better your final repair will be and virtually undetectable. Better to be slightly recessed than too proud if you can't get it exact as the paint will fill it flatter anyway.
Now clean the area with a panel wipe, allow to dry and dissipate and start applying with the air brush in several very light coats to the area that you have keyed working your way into the filled stone chip... Allow to dry thoroughly and then apply a few very light coats of lacquer... heat up gently for 30 mins with the hair dryer and then leave to harden, 48 hours before washing and polishing etc.
You can also use your spare tyre with an adaptor for the air brush reservoir instead of a compressor.