I have 24/7 that i would like to have a waterproof cockpit cover made for... i dont like shrink rap it is too annoying to deal with when you want to work on the boat over the winter. I figure that if i have a waterproof cockpit cover that extends over the engine bay that will be good enough to keep water out over the cold months.

Is vinyl the correct material for this?

sunbrella IMO is garbage it only lasts a couple years and if water pools it always leaks through. I have a sunbrella cover now its useless.

how much should this run me to have it made

Look for material called Triton. Waterproof and lite.
Used it for years on my Top Gun.

You probably have not had real Sunbrella as it easily lasts 10+ years properly cared for. You do need to treat it with 303 water repellant yearly, and 303 is not silicone based. Depending on your climate, a non-porous cover that does not breathe can lead to mildew, etc. Probably should add some breather valves to help excess moisture escape.

This is my problem before but somebody from the marina advises me to look for a vinyl material called Triton. This material is doing really good for cockpit covers and the waterproof system is really amazing!

You don't want a solid material like the vinyl on your seats because it won't breathe. No air moving in/out of your cover will lead to mold & mildew.

I have a vinyl cover that came direct from fountain, it has 4 vents and is completely waterproof. However, I would say it is even lighter duty than canvas. I like it because it folds up small and easy to carry, but I would never think of it as all weather all the time, my boat is kept inside.

Aqualon with sewn in vents/screens.

Exactly what he said. A good breathable material, like sunbrella, cared for properly and supported properly will last a long time. If you have pooling water, your not supporting the cover right. Use a camping tent as an example. Wen supported properly the tent works as designed. However if you don't use the support poles and allow low spots, water will puddle and it will begin to leak.

I, however, have also resorted to indoor storage. Not only do I not have to worry about a waterproof cover, I don't worry about sun beating my gel coat, don't have to wash the Bird droppings all the time. Where I am at, I don't even put my cover on any more.... I am on a floor rack and nothing is racked above Having a Center Console, I have a full length cover that buttons under the rub rail. It has been soooooo nice to not have to deal with all of those buttons when we come back and its even nicer to just drop the boat in the water and go. We do keep the cover in the boat incase we get bad weather, it is nice to have some shelter if the skies open up.