I would welcome learning of any knacks you have developed to effect a complete and invisible repair to chips and/or crazing in the gelcoat. I have filled a few small stress cracks and chips by grinding out with a Dremel and filling with flowcoat. Although the colour looks like a good match to start with, as the material ages it becomes darker than the surrounding original material. As for crazing defects - is it the same technique? Grind each line of the network of crazing out and fill and sand?