Floors get dirty no matter how meticulous you might be in cleaning, and since the grout has a surface texture resembling fine sand paper, dirt tends to rub in instead of rubbing off during the cleaning process. So even though sealing the grout will help with stains from liquids, no amount of sealer is going to change the surface texture of the grout. The grout is going to get dirty. So here it comes. Grout your floors with a grout that most resembles the color of dirt, which is gray.
Medium gray is best.
Many of my customers accept my advice, but others tell me to go fly a kite. I end up doing what I'm told, but I always bring the matter up. If you grout your floor with the dirt color, there is little or no reason to worry about sealing the grout, and this saves you a bunch of work. In any case, let's get on to the actual process. I would use the one that doesn't smell up the house.