DrZotro - I'm in the same situation you were in. I'm trying to integrate my 1080ti AIO variant into a full custom loop.
I noticed a difference in the FET (?) layout between the AIO variant, the WB variant and the aircooled one. Both the WB and the aircooled ones have the same layout, but, there is a 5th row of FETs (again, I think they are FETs) that seem to be SMD'd on the rear of the card for the AIO variant, but front side (die side) for the air cooled and WB versions. The EK WB seems to be compatible with the aircooled/ WB versions.
I haven't personally taken apart the card. I've only compared tear-down videos/ images of others.
Anyway, did you find a compatible block for the AIO variant?