Exposing & developing Provia 100 sitting in room temp for three years

I was cleaning a stack of 8x10 double sided film holders and found one that still had a sheet of film in it, 8x10 Fuji Provia 100 transparency film. I last shot Provia 3 years ago and this one film did not get exposed. It's been sitting in the basement, adjacent to the darkroom, at room temperature 70°/80°, depending on the season (darkroom is air conditioned 68°), so the question is, how I should expose the film?
Will a standard reading off a 18% grey card be alright, or should I overexpose, and if so, by how much?

Regarding developing, I'm taking the sheet to a lab that still does 8x10 transparency film. What instructions should I give them?
I know, it's just one sheet of film, but it is a gorgeous film, the colors are very natural, not saturated, so I would hate to waste it.. and I'll be up on the roof in the next few days, and want to take the shot from up there.

Thanks in advance!

Give it half a stop more exposure.

pentaxpete said:

Give it half a stop more exposure.

Click to expand...

+1

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that said, ive been exposing a ton of provia lately,
developed in coffee and dektol it makes a beautiful b/w negative !