Cabriolet tack rail upholstery

[1930.68B]

I am trying to find out what holds the upholstery down in the groove around the base of the package tray? (see photo) What keeps the upholstery from being loose in the sheet metal gap at the curve in the tack rail? Is there some kind of thin panel material that covers the vertical wall between the package tray the top surface of the tack rail?
The second photo is from Russ B's photo array. It shows the upholstery stretched tight over the tack rail and without the tray panel being installed.

Thanks

 

[1930.68B]

In the first photo where the wood starts to curve there is a vertical notch that was for the later style package tray. Should that notch be filled in?

 

[1930.68B]

Btt

 

[Bbobopuppy]

I think to better understand your question, I need to know are you using a kit or building your own upholstery? The grove is for the vertical upholstered cardboard panel that covers the belt rail, The grove holds the bottom of the panel in place. The package tray is also a covered cardboard panel. The shelf cardboard has some holes in it that allows the panel clips to slip in-between the cardboard and the fabric to hold it down into place. The metal package tray was made in two versions. There was the 4 clip tray and a 3 clip tray. If I remember right the 4 clip try was the earlier version (1928-1929)

 

[1930.68B]

We will be buying a kit but I wanted to get a better idea about what we will be getting into. Your comment "The grove is for the vertical upholstered cardboard panel that covers the belt rail." confirms what I expected. To get that smooth of a contour around the inside of the tack rail there just about had to be some type of panel material behind the upholstery.

Thanks
John