[Alan Lacey] " plan to capture SD PAL proresHQ intentially lower field first, "
PAL is always upper field first . It is my guess that you will NOT be able to effectively override this in the IoHD.
you can change the field order after capture -but it will NEVER look quite right best to convert the video first then capture.
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD