The old attic was just a nice flat roof that originally had some blown in fiberglass in it.  At some point the previous owner had added some fiberglass rolls on top of that, and then this past fall in a poorly timed project I blew in another 12″ of cellulose.   After taking that all out and redoing the ceiling, its now time to put some insulation back in.  I’ve saved all the blown in stuff,  but that won’t work for the nearly vertical sides of the skylights. For those I’ve used a base of R13 Fiberglass, running in between the framing.   This required alot of cutting as few of the studs are 16″ apart, and parallel.  I also realized too late that I should have done the far end before putting up the sheetrock, as its almost impossible to get in there now.   With this insulation in, I’ll use my air compressor to blow the rest of the insulation back in, as well as a wrap the skylight ‘tunnels’ with a roll of R30 fiberglass.  This should give me R43 on the vertical surfaces, and R50 or so on the horizontal.