To answer your questions...
1. see answer 3.1-Does anything care about the order of the prefix's used in the subform records or if there are gaps?
2-Are a Subforms records limited to 1000 entries?
3-I want to show empty options, so based on the type of item in record one I may want to add 4 empty subform rows. Would the best way of handling this be to manage the delete option with some
2. Yes, only 1000.
3. You can use
https://wiki.nubuilder.cloud/ ... formObject in Javascript (in the browser)
or
https://wiki.nubuilder.cloud/ ... formObject in PHP (on the server)
to programmatically use the data in a Subform however you want.
But I don't understand enough about what you want to achieve to suggest anything more.
Steven