toaster pickup history? measurments?

[grazioso]

hi guys

i just noticed that some of my mid 60's guitars have different neck pickups - it is overall measured from the bottom plate to the top of the cover more narrow by like 1/8 than the bridge pickup is and the bobbin is also bit smaller between the top and the bottom plate so it will fit there in the cover...when this was changed? when i look (with caliper) at modern rics i am seeing that both toasters are the same height...

[sys700]

I have original toasters on my 3 60's era Rics:

1964 330S/6-string - Long pole at bridge and neck. (A bit smooth. I have to run it through a compressor to get a good crunchy sound)
1966 330/12-string (mid-year) - Long pole at bridge and neck. (Crunchy, compressed sound like Byrds recordings - no compressor required)
1966 330/12-string (late-year) - Long pole at bridge. Short pole at neck. (Creamier/smoother sound and with better action across the entire fretboard (due to non-routed pickup at neck?))

I don't notice a difference in pickup dimensions but there are differences (long pole vs. short pole) that seem to have an affect on the overall sound. I have not measured the resistance of any of the pickups.