Silhouette vinyl help, please? (More wedding stuff!)

For a script font like that, check Creative Market. You will find a lot of them there that are similar and most are pretty reasonable.

I don't think shellac will work all that great over the top of the vinyl. If I was going to use vinyl on wood like that I would probably paint or shellac the wood first so it's completely smooth, then use exterior grade vinyl with permanent adhesive on top of the sealed wood. 

Alternately, if you want to use the vinyl as a stencil, I'd make sure the wood is as smooth as possible to make sure the vinyl seals tightly to the surface so the paint doesn't bleed through. You might want to try using paint sticks specifically for stencilling because it's drier and much less likely to bleed under the vinyl at the edges of the lettering.

Before taking on anything big, I would experiment with both methods on a couple of smaller projects first to see what looks best and/or works best. Good luck, those look like fun projects!

Gorgeous ellewood! I have been wondering how everything went!?

It looks amazing!

Fantastic! I love the sign.