Mine runs on Morris's SAE 40 at a consistent 22psi once warm. I too have fitted one of David Jones's improved mixture screws to the Solex with the result of a quite fantastic improvement in low end flexibility.
36 4G, 37 VH, 54 KH(A), 75 Healey 1000/4, 52/53 ex ISDT KHA (project).
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.