Flooring Tile - Marble backsplash planning questions

I am getting ready to start my kitchen backsplash (31 sq. ft.) in a diagonal marble (crema marfil color) 6x6 with an occasional 2x2 black granite piece. I have the following questions since Marble is not like regular tile:
- Do I need a backboard on top of the painted drywall before I use mastic or what ever will glue the marble to the wall?
- Do I use Mastic or Mortar? What’s the difference? In other words, what do I need to adhere the tile to the drywall?
- What is thinset? Do I need it?
- Are 1/16 spacers fine or should I not use spacers for marble?
- What size trowel should I use?
- Should I use sanded grout? Do you recommend a special type of grout?
- HomeDepot has a wet saw for around $90. Would this saw be fine with Marble? The HD salesguy said it would work fine but I am not convinced. Do I need a different blade for marble?
- Should I invest in nippers or what ever is used to break small sections of marble?
- The HD sales guy told me to purchase 12x12 pieces and cut them into 6x6 pieces since it would cost me much less. I have table saw cutting experience and I consider myself handy, but would wet cuting the 12x12 pieces into 6x6 be a good idea?
- Any links with marble specific info?

The crema marfil color marble costs less than $5/sf and it’s .37 POL??? (in case you need to know the quality and type).

Thanks in advance and excuse the huge list of questions.

Mario

I also saw you question on John Bridge's forum. You will get good answers there.

Both Home Depot and Lowe's have similar wet saws. They are similar in price and looks, but don't be fooled. The Lowe's saw is CRAP! I actually bought it to do a small job and returned it because it took forever to cut through the marble - reason being the motor was on 1/3 HP. I then looked at the HD wetsaw. It had a 3/4 HP motor on it. I purchased it to do the entire bathroom in marble. I also purchased 12 x 12 tile, but for the shower floor, I cut them down to 3 x 3 without a problem. I was actually impressed with how well that $90 saw worked.

Personally, I prefer to use durobond thinset mortar as opposed to mastic.

I wouldn't use a sanded grout on polished marble. Get a non-sanded grout and use spacers that are no larger than 1/8".

I would use a 1/4 x 1/4 notched trowel to spread the thinset.