JeffS65 your anecdote delivered me a smile. 
Caused me to reflect upon what in hindsight provided me with a breakthrough with pinky manipulation.
Sharing it here in the hope it might assist others.
Indirectly my underlying motivation was fueled by an intense desire to play two specific songs, both of which mandated pinky dexterity in order to do so led to my 'pinky playing' light bulb moment. That practical purpose context sustained motivation for the necessary perseverence & determination driving active interest in the repetition necessary in pursuit of achieving that specific goal of the many to be met in order to play those songs.
[br]The two songs were "She Loves You" in the key of G as taught here on GT by Dave C, where in the verse at a clipping tempo of 150BPM, the fast accurate strong placement of the pinky is required for the Em7 off a barre G (watch from 2min10sec - timed links not possible on GT TMK) followed by a barre Bm. It's less challenging off the open G and can be played that way as rhythm, and from watching live performance videos, John played it alternately that way as the rhythm part with George's supporting lead guitar. But the open G doesn't work as well into the abridged version arranged by Dave in playing an conjunctive adaptation of George's parts on a single guitar. At the time I took the song on, it was a significantly challenge to my then skill level. Not open G specific, but a fourth finger dexterity breakthrough nevertheless.
[br]The second song perhaps the more relevant, was The Eagles epic "Lyin' Eyes" in the key of G which doesn't exactly loiter either at a tempo of 133BPM. The verse here pretty much mandates a pinky open G in order to follow with the Gmaj7 at its tempo with the liftoff and overall timing of notes played on the 1st string. Even more challenging, is the return from the open D7 or D (Eagles played both and either fit) to pinky G which needs to be executed consistently accurately and quickly in order to repeat the verse progression. And it's a long song where one needs to do that over and over and over consistently. The placement of the pinky has to be accurate or the high G note will not sound as it should juxtaposed with its immediately following liftoff timing to the E note preceding the change to Gmaj7. Specific relevance of pinky G in practical application here. It doesn't challenge stretching so much as overall pinky control & dexterity, specifically accuracy, consistency, strength and co-ordination. Stretching distance in barre application is still my personal pinky's Achilles' Heel.
I'd been aware of and utilised Christopher's exercise lessons, but it was application through sheer brute force of repetition and time provided by the intense desire to accomplish those practical song playing goals that provided the breakthrough for me with pinky dexterity. That said, I can't say I'm looking forward to the super-stretchy challenges awaiting in the Blues course for my tiny pinky. Ouch!
In summary, not in contradiction of Christopher as I wouldn't dare be so presumptious in deference to my sincere admiration of and respect for die Meister, the song I'm figuratively singing here as a relative nOOb myself is to find a song/s you absolutely love within a practical realisation of probable accomplishment which utilises the pinky in a motivating pragmatic way provoking active attention and maintain focus and interest other than just reliance soley or even predominantly on a dry exercise. Do use the exercises too, with quasi religious frequency in daily application, but, because we are human and learn best doing when motivated by driving desire and interest, as an adjunct exercise to the core motivation.
Merely my perspective given what worked and continues to work best for me in practise.
.....[br][br]Moral is, your hand is a system and has spent your lifetime learning how to do things as a team. Now you're trying to ask them to be a bit more independent. But you're not used to using them in this way so they'll more easily default to how they normally are asked to move and work.