I use both the .12 and .15 depending on the mat. The Rags are 100% cotton and can be ruined by a dull blade, the SRM's are a bit tough and I like the .12 on them as it seems to cut a bit better. I am probably being a bit conservative on the 4 cuts, but those 4 cuts were on a 30 x 40 with a 3.5" reveal. On 16 x 20, or 24 x 32 ( I size I just prefer), I will go a bit longer. Also if you use Black core, the blade will dull a lot faster. But still blades are so cheap, and a dull one can ruin cut number 8 on a double mat and there goes the whole deal.
The fresh board for each cut is really important IMO. You can use scrap board for this and you don't have to move it very much just enough so the blade hit's a new fresh piece of mat underneath each time. On Crescent 32 x 40 dollars a board for Paper? SRM, etc. Remember anyone's base mat is essentially all paper with no ability to resist yellowing and you will quickly see the nice white edge on the cut turn yellow, which IMO ruins the board. The SRM's do a great job here, are still a alpha cellulose but won't yellow on the cuts.
The 2200 is great machine, a bit finicky and IMO is easy to get out of true, at least mine is but it can make a nice cut. Only wish it would do 8 ply in a single cut which it won't so I still have those cut for me.
Paul Caldwell