We are pulling systemForm data from Dynamics with the REST API:

https://jj-----jj.crm6.dynamics.com/api/data/v9.1/systemforms?$filter=objecttypecode eq 'lead' and type eq 2 and componentstate eq 0 and formactivationstate eq 1 

This works well except we need to determine which is the default systemForm.

The way I understand it this can only be determined by returning the Form Order.

I can't see a REST API that returns this information. Does anybody know if this is possible via REST API? If not how do we determine the default Form to work with?