On cutting the pink stuff without all the fluff. I've used some of the cheapest thin paring knives I could find. I figured I'd use them and pitch them. After cutting hundreds of feet of foam they are still reasonably sharp so I kept them. They have 3" long blades, came in a pack of 4, and were only sharpened from one side. Yes, that cheap.

They have a flat side, and a bevelled side. I used a cutting guide, then cut with the knife's flat side against the guide, and the bevel facing away. That way the bevel pushed the blade into the guide. On 1/2" to 1" sheets I'd cut all the way through in one stroke. Thicker sheets I scored the foam to around half way through, then slipped a 2x4 under the cut line, and put a bit of down pressure on each side to slightly open up the cut line, and then cut it the rest of the way through. It hasn't been any problems to cut 2" thick foam this way. If you aren't to worried about the edge, you can just cut half way through and then bend the sheet at the cut line and it will break off relatively cleanly.