I believe sealing is not recommended prior to grout.

I'd use Miracle 511 prior to install and Miracle Porous Plus after install.

Thank you...i have been doing research since my original post. Any experience or comment about Drytreat Stainproof Plus? Thanks.

I would check with your installer. He's likely planning on sealing before grouting and may prefer and have experience with a particular product. His install guarantee may be tied to his preferred product. It would be if I were doing that. Good quality check to determine this before install.

No experience with that. Been doing this for 35 years and like most pros, we tend to use what we know is a quality product (appropriate for the application) that has provided consistently good results.