Electrical characteristics of Repro heads vs. Phono carts..?

I've been trying to find specs on (studio) repro heads without much luck.  Does anyone know where I can find this kind of info?

My impression is that:

(1) tape playback
  - and -
(2) vinyl LP playback with an MC cart  

require roughly the same gain, overall.  (Which is: a lot of gain  :) )

However, I am more interested in the internal impedance of studio repro heads, also their inductance, in addition to typical output voltage etc.  I recall reading on the Manley Labs website once, in a discussion of their all-tube repro preamps, that their gear was designed for Hi-Z (high inductance?) heads rather than low inductance.   This is all I can remember seeing anywhere.

If anyone can point me in the right direction, I would certainly appreciate it!

- Mike