I add a layer of that Uv/blacklight glue to the end before use and self adhesive velcro to the wires to prolong the life of the lights and keep the wire out of the way.
I have used it on patio furniture and porch furniture. A little on the stiff side but it has held up fine outdoors for 3 years on my own outdoor chairs.(I bring them in in the winter, but they are out in the sun and rain half the year).
Sunbrella makes upholstery fabrics for outdoor furniture. You may want to consider using it. It has many of the same properties as their boat cove material.
It should be fine to get you started. It is designed for heavy materials and the feet are interchangeable with with some Juki's and Chandler/Consew machines.
I do vinyl repairs, but this one has been done by someone else. Quite poorly I might add. So repair is pretty much out of the equation.
It looks like Just Dash is the only option as a junk yard wants $1,000 for a 60 year old one.
It does not have the french seam or I would have covered it myself. It is a molded vinyl/plastic one piece cover. Just dashes finished price with shipping and color match is closer to $1,500 with a 5 month lead time. Just wondering if there were other options.
Try Craigs list. I just sold a Chandler for $600. Jukis are nice but my Chandler was basically the same machine. In fact the owners manuals were identical.
Now comes the real question. Who makes true left hand shears? Not ones with a reverse handle but reversed blades. Many years ago you could buy them but I have not been able to locate any in the past 10 years.
I use the same method as Gordon but I use a foam bun. They have a skin on one side and stiffens the seat and evens out the weight. Plus they are cheap.
Never talk poorly of your competition. I work for a few boat dealers in my area and even though they knew my competitor personally they still use me. He came in talking smack about me. Now everyone knows he spoke ill of me. I always give them priority treatment and that is important to them.
As with anything if it is not what you normally do it will take a little longer than the stated times. Plus the wet and mold and bugs, associated with boats
When I only did furniture the first chair in a set of 2,6, or 12 took a long time but the last ones flew by. So one off custom work takes longer, just as having a pattern speeds up the job. Maybe some one should make ready made standard seat patterns to sell for the common cars. Oh Wait you can already get those from Ecklers.