Here is my run down on Gelcoat and what I did to match the color on one of my project boats. For the hull - White I assume you can use the White Gelcoat - not neutral.. Get a Gelcoat Color pack and get a pint of the gelcoat - mix the whole pint in a 1/2 gallon sealable mixing can / container. Mix colors slowly and take a q-tip and dab a spot on the hull until you get very close to a match - For WHITE you will never get an exact match but you can get really close. NO MEKP at this point just matching the hull color.
Prep the area, I sanded the area and if a deep gouge I champhered the hull to a 1/12 slope - you can use a 200 grit paper block to knock down the edges. Clean with Acetone everywhere. Get another pint can or smaller - clean and pour the gelcoat - enough for 1 application and measure it out - I use a paint cup with numbers Oz. add the required MEKP and apply the gelcoat. I worked in layers, about 6 - building the low areas up until I have about a 1/16" left for the final 2 coats. YES, Long process. You can also use filler but the gelcoat on these boats is about 1/8" thick. also - use non waxed, for the sealing of the gelcoat you will want PVA to spray over the repair. ... OK Final coats - I used a really small fine roller, I didnt get brush marks and the finish is very close to an orange peal with paint. Build the area out around the repair and up... You will sand it, compound, and wax. Once the final layer is on the boat spray the PVA all over the repair and walk away till the next day. Clean the PVA off with water, use a 1000 wet and dry to knock down the high spots, move to 2000 wet and dry, lightly compound the area and add a final wax....
If your boat is or shows chalking, then you will want to compound and wax the full boat after you see how shinny the repaired area is..
If you re-gelcoat the non skid then I highly suggest the Neutral Gelcoat, add some white Gelcoat as the base, Some (6-8 drops) Black and Brown and 1 yellow tend to get very close to the Ericson Non Skid color. Add some fine non skid sand to the mix.
The secrets to the color match is have the color in bulk, then use small amounts with the hardener building layers.
Hope this helps. I repaired a 4' section of crushed hull and deck using this method...with good results