Using Flex Forms for large list of valid members

Summary:

We are exploring the use of Flex Forms to enable large data uploads into our Planning application using Smart View. We have a few dimensions that have a lot of members that need to be valid in the form. I am running into the following issues:

1. If I include the full list of valid members across multiple dimensions, it exceeds the maximum cell threshold. Ideally, we would be able to specify all valid members without the form actually trying to pull data for all of them
2. If I turn on any of the suppression options (Database level, Missing Blocks, Rows), the form opens without any members and I cannot add new lines that meet the valid member list