I'm not sure I'm sold on the looks of the sill seam finisher, but then again my car has never had them.
That said, that seam is rather ugly.
The problem with the finisher is it is a nice moisture/dirt trap, perfect breeding ground for Rust.
I'm actually contemplating just getting some stick on plastic chrome door edging and just sticking it to the outside of the seam.
Was debating that for some time but its really easy.
When the car is fully primed its stuck on the rotisserie, flipped and the underside of the floor Raptor finish then top coat same as body, all 2k.
No hard edge mask on the body, just careful application underneath and allow feather out onto underside of sills etc but make sure inner and outer edges of sill seam/flange has good coat.
Prep and paint trimmed ready to go sill finishers, now the choice.
Either small drill holes in bottom edge of sill finisher, ( done before paint ) either spot fix with PU adhesive or use trim clips, same style as top wing finishers to attach trim finisher.
or my choice
Mock up and fit finisher, prep and paint, then fit finisher with upper moulding trip clips, then using a grey PU adhesive carefully seal the edge of the trim to the flanges, pointy finger is best, push it in then wipe off excess so it cant be seen. Because you have painted the trim finisher first you can wipe the PU adhesive off easy with a good de-greaser.
Then when the body gets flipped over for top coat return mask off the rear of the already painted sill flange finisher, prep the paint on this front side, the body can now be now prepped ready for paint and when you refinish no one will be able to notice the return mask on the bottom edge of the sill finisher. If it is a little bit harsh because you were heavy with the gun or forgot to remove the return mask and feather with some blend out thinner or slow thinner then hand off with G3 on this edge.
When I get to this stage I will put up some pics.
There are many ways for everything but this is prob the method I am using.