https://www.amazon.com/dp/B003QLH0NA..._ay8Zub1TVWY1M
Does these stuff work ?

The only problem I found is that some sun block lotions could melt it and ruin clothes.

Is there any type of clear to go over top

I've used for side bolster pieces on my previous boat (91 Pachanga). had the boat for 5 years and never had an issue. Never had to use it for seating surfaces though. at $15 can why not try...still a fraction of the cost of replacing the vinyl.

There are a few threads on here about vinyl paint. I've personally have had great results using it. In sun and any sun tan lotion.
https://www.duplicolor.com/products/vinylFabricCoating/

^^^^ what above said as the Duplicolor product is better. If I remember correctly, it is a cleaner / prep spray 1st and possible adhesion application 2nd then the Vinyl color paint lastly. It is a 2 part or 3 part application for the best results. Its like anything to do with painting - the finish product and longevity of it is all determined upon your prep work first.

I have been very impressed with the Duplicolor product!

I've used both SEM and Duplicolor on car applications. I've found that the Duplicolor has a tendency fo "fill" the grain on vinyl if laid on too heavy. The SEM actually soaks into the vinyl and doesn't scratch as easily. Just my experience.