Rewired our S/C dragster this winter. Went with WeatherPak connectors as well.
Also used the
Dedenbear Multiple Relay Center and love it. Can't have too many relays... And it helps to have the fuses and diagnostic capabilities it gives you.
Don't rely entirely on crimp connectors. Preferred is crimp it, solder it, then heat shrink cover it. PITA? You bet, but it will last.
Also use bigger wire than you think. If you think 18 is good, use 16, etc. Can't possibly go wrong with bigger wire.
Grounds to the chassis are good, to panels are always bad. Ran a separate ground from the dash all the way back to the battery. Dash stuff is so picky.
Rewired the car completely, built an entirely new dash, all new components (racepak dash, delay box, switches, etc.), and proud to say it worked first time perfectly, and haven't had an issue all year. So it can be done.