[Daves55Sedan]

If you got the repro of the factory clips (7 needed per side), it looks like you need two different size holes.
The only thing I can do to get exact information is run out to Dans junkyard in Macoutah where there is a black '55 Towne Sedan with all the bells and whistles. It seems to me last time I saw it, the rocker trim had fallen off one side so the holes were exposed. I could take some cardboard, sissors and punch out with me to make a template and take measurements. He may have some original '55 skirts out there too that I could look at.
Thing is, I am certain they are closed due to the Chinese plague.
That black '55 has the accessory sun-visor over the windshield too. I always wanted that for my '55.