Repaired a few stone chips last night and just now. I have 3 very small ones towards the tops of the wings where they meet the windscreen pillars, and a large one (probably 2 square mm area) on the bonnet. The bonnet one and one of the small ones have taken it down to the undercoat.
Splash of red on 2 of the chips yesterday and a splash of clear on the other 2, brushed around the painted area with a model brush with IMS on to thin out the excess beyond the chip and left them to dry for 24 hours.
I was surprised how tough the paint had dried in 24 hours. I was giving the clear excess a good rub with a moistened cloth which had Mer abrasive polish on it. After 5 mins I gave up on that and started buffing with an IMS moistened cloth and got it down level. A quick polish up with Mer, and I couldn't see any evidence of repair, completely invisible. The IMS was quite slow taking the paint up, which was a good thing, not easy to overdo it and take all of your paint off with a few cloth swipes.
I then did the same on the red, just to get it slightly concave and have applied the clear to excess, to get rubbed down level tomorrow (weather permitting) - hopefully it'll be just as good a finish, although the bonnet chip will probably be the biggest challenge.