"are you using an adhesive to hold them down?  If so then nothing more is needed, if not then yes use your steel.  Countertops are not designed to be used as seating "

"over kill  "

"PVA or Glass fibers are all that are needed then"

"too many variables to answer, how thick is you piece? How much of the piece is supported by cabinets or whatever, how long is it, how wide is it? is it indoors or out? If you want a defined answer then you need to be specific with your question. "

"Contact Blue Concrete they can make any color pigment "

"I would use StoneLok - it is designed to be emerged in water"

"Buddy Rhodes sealer does not last too long exposed to the elements.  You should reseal every 6 months.  "

"i would put a coat or two of resin on the bottom "

"think styrofoam - it is cheap and easy to form - you can make that pot pretty easy with foam"

"That will look great when you do a scale to size Fenway Park haha.  Green Monster!"