Sealing Marble Tiles Prior to Grouting

I am tiling a shower with 12"x12" marble tiles. The tiles are polished but each tile has some "pores" where tile veins and other "imperfections" are. I am getting ready to grout the tiles that have 1/16" gaps between the tiles and I have some questions before I get started:
1. Should I seal the marble tiles before I grout them? I am worried that the grout might collect in the veins and imperfections and I won't be able to get it out when I spounge down the tiles to remove the excess grout from the tiles.
2. Instead of spreading grout across the entire tile surface, should I just use a "cake-like" decorating tool to press the grout only into the grout lines? This would minimize the problem mentioned in #1
3. I eventually need to caulk the tile seams and want to create a professional look. Should I buy the ProCaulk product (about $25 => https://www.buyprocaulk.com/?s_kwcid=procaulk|1801931959&gclid=CJDIiLTDiZYCFRUjnAodhGoaEQ) or do you recommend another way to create perfect looking caulk lines?

 

What does the manufacturer recommend, that would be the first rule. And use only adhesive recommended for marble. Some colored adhesives can bleed thru the stone.

After that, yes, I would seal after installation and before grouting. Once sealed(carefully follow directions), you should be able to grout as usual, not worrying about where the grout is spread. There is no way you will not get grout on the tile surface, no matter how careful you are.

My last comment would be........are you really sure you want marble???

 

Use a quality modified thinset. As mentioned by Bill organic adhesives can stain natural stone, and shouldnt really be used in wet areas anyway. Use non-sanded grout on the 1/16" joints. Sanded grouts can sometimes scratch polished marble. Some polished stones will not take much sealer and will sometimes streak from the sealer. Try sealing a sample piece first. Sealing prior to grouting may not be necessary unless the stone is very porous.