and, are all 3 interfaces connected for Loop Sync?
More info, in case this is all new to you:
1-Each 192 can provide a total of 16 IO
2-You said you routed your ADAT outs correctly, but to where? The ADAT outs need to feed some kind of converter and you haven't mentioned any.
3-Are you using only the 16 mic preamps in the Ctrl24? Have you connected those to the analog DB25 inputs of the 192 pair?
4-Are you connecting each 192 to a separate HD card, or are they daisy-chained to a single card(either way should work, but it may be worth trying the method you have not used yet)
5-The ADAT IO only works at 44.1 and 48K(can't use them for higher sample rates).
6-just a terminology thing, but the "standard" 192 with 8 analog IO and 8 digital IO is usually referred to as "8x8x8"
