It is a difficult problem and depends a lot on the type of cork you use. I used 1'x2' tiles with plain edges in my International. That way, I could orient the tiles any way that minimized wastage. I ended up with just a handful of small pieces.
What I did was measure the floor, make a CAD diagram of the floor, and try fitting the tiles in different orienrtations and starting points until I found the best fit. I must have tried 10 different orientations before I found the optimal one.
I tried it with tiles with interlocking edges and the waste went up dramatically to about 1/3 of the cork because the tiles fit in only one orientation.
I put mine down with water based contact cement. I didn't roll mine, but I would if I did it again. Once the tiles touch, they are pretty much locked in place. In the confines of the trailer, it is very difficult to place the tiles exactly right. I used a roll of brown paper that was intended for paint masking. I would put the paper down in two pieces, place the tile, and then lift one end and then the other to remove the paper. That way, the tile couldn't be grabbed by the contact cement prematurely.
What I am trying to say is that without doing something like I did with the layouts, it is almost impossible to guess how much cork you would need.
John W. Irwin
2005 Classic 28 "Sabre-Dog III"
2013 Silverado 2500HD Duramax/Allison LTZ
WBCCI #9632, TAC TX-10