Why does it matter? (Full Swing should typically be a good safe choice for most Arduino compatible boards.)I like the idea of full swing my self.
IMHO, I believe the oscillator is more stable in this mode.
It just means one has to have an entry in eg. BobuinoFullSwing in boards.txt (with low fuse set to 0xF7), which is no big problem.
Use 0xF7 in Nick Gammons boot loader pgm for low order fuses for 1284. http://gammon.com.au/Arduino/Atmega_Board_Programmer.zip
Again, thanks to you, pito and Crossroads.
@Crossroads I realize you copied and pasted the elements in the schematics, but for others C1 and 2 are 15pf and R2 is 220R.