Hi @DaveLawrence ,
The output routing switch on the SD8 is designed to work with up to three units on an AES50 line. The maximum for inputs would be six SD8s - which would use all 48 channels on the AES50 - but you would still be limited to 24 outputs.
You could have SD8s on both X32 AES50 ports if not being used to connect to other consoles.
IIRC there isn't a limit (or at least no one has had enough hardware in the one spot to test.)
You are limited to the first 6x SD8s in the chain on one of the AES50 legs in terms of inputs (6x8 = 48, which is the limit of a 48kHz AES50 stream,) but you could have 20x SD8s connected, (the last 14 of whose inputs wouldn't reach the console; they'd be "bank-shifted" to nothingness) but those SD8s' outputs would still function (though with any more than 3x SD8s in the chain you end up with something being duplicated.)