You will do quite well with Superia 800, even if you expose it at 1000.
I usually expose it at 500, not because I believe that it actually is 500 speed, or because I believe it it appropriate to routinely overexpose color negative film, as some do, but because I usually use it without a meter, and using 500 vs. 800 makes sunny 16-based exposure calculations more streamlined, and allows for some slop. Overexposure won't hurt a pic's chances of being printed as badly as will underexposure, so better to go down 2/3 to 500 than up 1/3 to 1000 for sunny 16-based exposures. If using a meter, I always use box speed for color neg film, unless I am going for an across-the-board over or under exposure.