Leak 600 Sandwich speakers

I recently came by a pair of Leak 600 Sandwich speakers: Sandwich 12" bass
driver, 3½" paper cone mid and a plastic dome tweeter (I know, most of
the 600s had a Sandwich mid as well, but not this pair).

The mid drivers in both were stone dead (rattle croak fluff) and as result I
need to fit some different mid units. The original mid units had around 16
ohm impedance, I believe, and the new ones 8 ohms; some work is therefore
going to be needed on the crossover points as the current values will be
well off for 8 ohm drivers.

Does anyone out there have any technical information about these speakers:
existing crossover
frequencies, bottom end driver impedance, tweeter impedance, a crossover
schematic would be amazing but, I suspect, unlikely to exist in the wild,
Thielle Small params for the 12" driver would be more amazing still but I
guess even more unlikely.

I am thinking about designing new boxes and dropping the crossover frequency
between bottom and mid a bit as I have to attack the crossovers anyway, so
any info whatsoever would be a big help.

TIA

Paulos