It's possible that the Yosemites' actual magnifications may not be quite as specified. I evaluated an 8x30 back in June ( http://www.birdforum.net/showthread.php?t=116600 ), but unfortunately didn't bother to measure the true magnification.
The effective eye relief of the 8x30 model could be longer. It's limited by the design of the eyepiece housing rather than the optics because the eyelens is recessed more than necessary.
Henry,
If I recall correct Ed Zarenski (EdZ) measured the true magnification of the Yosemite 6x30 to be 5,8x.
Regards, Patric