Hi Ian,
Thanks for the further explanation. On that point of filling a table in the Parametrization based on the choice in an OptionField, That sounds an awful lot like having dynamic defaults on fields. Which is an often discussed topic in our product (see Function lookup - set default values optionfield or Change table content when changing dropdown menu selection for example). However as of now, this is not an option.
One option (which you’ve already figured out) is obviously to use the SetParamsButton. Depending on your specific use-case another could be to prepare several different tables in advance and have them all at the ready in you Parametrization (mind you, if the tables are very large this could lead to slow params calls) and adjusting the visible flag of those fields based on the choice made in the aforementioned OptionField.
Would that work in your case?