I got the P. sagittifolium var. at, if memory serves me correctly, the USF Botanical Gardens sale at Tampa. It was (incorrectly) labeled P. imbe ilsemanii. Later, I got a cutting of P.Jose Buono from a trade with a good friend from St Pete who had ALSO bought THAT labeled (incorrectly) Philo Imbe Ilsemanii. I think at this time (mid-2000's) a few different Philos were making the rounds all with the same (incorrect) name.
My experience with both of these has been that the variegation is extremely variable. I can have extremely variegated leaves with a ton of white, half and half leaves, almost all green leaves, and leaves that are green but variegated also with lighter shares of green. The variegation on them is chimeric, non-patterned so its bound to be highly variable.
One of the main hallmarks of Jose Buono is that it is pretty fast growing and the leaves can reach 2+ feet long. The sag var not so much. The auricles on Jose Buono and on the sagittifolium are close in morphology, Whipple's Way does have a much deeper dive between the ears