The reverb tank on my Selmer Treble n Bass is completely shot (missing springs, one remaining has broken away from the transducer), but I'm really struggling to find any of the specs to source a replacement.

The unit is about 9" long with solder input and output connections and mounts for two springs. The closest thing to a part number on the tank is "OX" printed on the inside - I'm pretty sure Selmer used Hammond units back in the day, so I was hoping this would match up with one of the Hammond organ models but I haven't had any luck. Might be worth pointing out that the input transducer is red and the output is green, but I have no idea if the colour coding for impedance is consistent over time and between manufacturers.

If anyone could shed any light on the spec of this unit I'd be very grateful, maybe someone knows about vintage Hammond gear or the reverb matches those used in other amps of the same time period (early 70s)?
The accutronics website tells me that the colour coding on the transducers is for input impedance of 1475ohms (F) and an output of 500ohms(A), however I know that the reverb is transformer driven - all other sources tell me transformer driven reverbs should have input of 8ohms(A) and output of 2250(B), which of these is wrong?

Here's a schematic for the amp http://www.vintagehofner.co.uk/selmer/schematic/tnb2.html showing a TI88(?) transformer driving the reverb and the ecc83 as for recovery. Is there any chance anyone might know or be able to work out the optimum impedance from that?
Take it to a decent tech and ask them what you'd need to replace it with. Most will do this for free (advice that is)
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Been chatting with the only tech I know of who's fixed up a lot of these, but he hasn't much experience with the version with reverb, so can't tell me anything for sure, but he's pointed out that a higher input impedance could be for bandwidth restriction - so I shouldn't rule it out.

I think I'm probably gonna pick up a low input impedance tank to start with, because of similarities to old fender reverb circuits and because there a production models to that spec, if it doesn't work then I'll just have to order a custom one. At least I can definitely rule it out that way.