Another repairing gelcoat question

Hi all!
This has been discussed a lot, and most of it I have read.. but I still want to make sure I do it right before I do something.

During one of the last sails, I scratched a keel against concrete ramp. Scratches are 2-3 mm deep. One dent is deeper - goes through white gelcoat so I can see black there. The length of scratched area is about 2 ft. I hate that ramp.

Compared to the rest of the boat, this area now looks totaled. I want to try to repair it myself.

I went to West Marine and after talking to them I bought West Marine Gelcoat Finish (part 3745478). I was told to clean up the area, apply the Finish, let dry and start sanding with 600 paper, then apply again, dry, sand, and go up to 2K or whatever...
I was told this Finish would act both as a filler and the finish. I've seen Formula 21 recommendation a few posts below, but this was just a filler. I'm confused.

Is this right approach? I have never worked with any of this. My hands are shaking already, and I have not even took the cover from my boat yet.

Thanks!

_________________
Yuri
Hobie 16
Laser Vago

I cringe everytime you ding my old boat.

I'm just sailing it.

_________________
Yuri
Hobie 16
Laser Vago

I know, I'm just giving you hell Yuri Stuff happens sometimes regardless of how carefull you are.

I know. No problem.

But back to the subject. Can you all please tell me if what I'm going to do is right? I'm afraid to touch the hull.

Thanks!

_________________
Yuri
Hobie 16
Laser Vago