I also carry my 3/4 RR pad burrito style in my MYOG pack.
The main body of the pack works out to a volume of approximately 1660 cubic inches or 27 liters. As near as I can figure the pockets add up to 761 cubic inches or 12 liters. So my total volume adds up to 2421 cubic inches or 39 liters.
My pad isn't visible in the picture but the pack is filled with my gear that I carry for one week. That includes food, fuel, clothes, quilt, pad and cook kit which are all inside the main pack compartment.
The pad is rolled and inserted first. Then my pack liner of a 2 mil trash compactor bag goes in next. I then pack in all of the gear listed above.