I had the fingers routine in training as well - it struck me as a bit odd.
Surely the attitude regarding reference point on the plane (coaming, cowling) with the horizon will vary according to how high the student sits! We don't all come in one size. And also....
Many women have fine, slender fingers.......then you could have a brickie with hands like shovels and huge fingers. That last sentence sounds a bit daft, but you get my drift!
It was the prescribed teaching technique, but I found myself memorising visually what the required attitude would be for each particular circumstance - then backing it up with the instruments, While the instructor chanted Lookout-Attitude-Instruments every 3 seconds into my right earhole!
On the other hand, in the initial stages of 'attitude' flying it must be fairly hard to convey exactly what is required to people. Imagine if they had you fetching out your vernier gauge! In which light, the fingers method appears a bit more commonsense.
My instructor did stress that the fingers routine was in there to give an initial rough idea of attitude flying and had no problems in dispensing with it once the attitudes had been learnt.
I liked your B737 scenario
Regards,
JH