After a long day of modeling and figuring out sweeps and lofts, I finally sketched in the 2 steam ports and 1 exhaust port.
The outline of the ports can be seen in this see-through. The steam ports are fore and aft, with partial horizontal passage.
The front view of the saddle shows the exhaust port originating from the steam chest seat to the inboard center of the saddle (left to right in following picture).
Nothing about this was simple! The exhaust pipe has multiple cross-section shapes, and very organic curves. Both of the steam and exhaust ports are probably a bit of simplification, but given that the CK Holliday itself is a model, the real engine probably has the same “feature”.
This solids rendering shows the recesses of the ports, and the tappings waiting to receive the steamchest.
