I'll add my two-cents too. I'm not a pro but I have used the SpectraLock twice now. I found it easier to use than cement-based grout. I bough the smaller sized containers so I didn't need to measure/divide.
I found the small sizes where just right regarding the amount of time to apply before it hardened. I used a "epoxy grout float" from HD
http://www.homedepot.com/p/Custom-Bu...w&gclsrc=aw.ds
Regarding the water clean up. On the first epoxy grout job (the walls and ceiling of my steam shower build) I used the packages of cleaner. But when I did the pebble floor, I did not use it. I found the residue left a glossy, wet look, on the pebbles which I liked.
One key to a professional looking job, IMO, is having enough light to see what your doing. Most bathrooms are lacking in light (and can be even worse during the remodeling). I bought a "500W work light" that really lights up the space, and good lighting is really important. Don't ask me how I know this.
Good luck.