I used some patch paste from Spectrum Fiberglass on my '88 Tristar that matched very well.
They have colors matched to manuf. and gel color.
It also appears from the photo that you may need to 'whiten' the existing fiberglass area around the patch as it appears yellowed in the picture (might just be the computer image). I've read on TT where some have used a 'Snobol' type product to remove tea colored water stains from the fiberglass. The bottom of my hull was done that way and it made a huge difference in the color.
Patching the gel was new to me as well, but I suggest using parchment paper or wax paper over the wet gel paste. The wax paper doesn't stick to the gelcoat paste, but makes it much easier to smooth out the paste and then easier to sand down.
Lookin' good though as I've been following your entire thread.