Want to try something beside Sorta Clear 40?

Try thining RVT silicone with xylol about 1.5 parts xylol to one part silicone right out of the tube.
I used GE Silicone 1.
Mix really well until it looks clear. Some bubbles may appear but they go away.
You’re ready to use it just like Sorta Clear 40. Set up a jig and spread it on with a straight edge.

There’s plenty of info here on how to do that technique so I’ll leave that up to you to sorta that out. 

Here’s a short video of the sample piece I made, used three different ways.
The layer of silicone is about .010” thick.

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I think the nylon cloth worked best. Light touch, easy blobs while dragging.
I would think that Rosco would behave the same with this surface.

Behave Rosco!