Tom, you are correct, the thread size in question is a 1 inch -14.
As seen in the pictures, all our current housings us this size of thread at this location.
Older housings had a 16mm thru hole and really old housings had a 1 inch thru hole but we provided (2) sleeves, 1/2 thru hole and 16mm thru hole, so the customer could decide.
We never had a 24mm thread on any of our housings so not sure where that information is coming from.
IF anyone has any technical questions or just general questions please email us at-orders@aquatica.ca and we will do our best to answer in a reasonable time frame.
Everyone have a great weekend😊