PUM - Creating and applying change package in non-Oracle DB environment

We are upgrading our HCM application to 9.2 / PT 8.53.12 with DB2 OS 390 as database. We set up a demo environment (actual environment not image), updated to image 6 and used it as source to upgrade development environment and test environment. After runing initial pass, testing revealed some bugs for which there are fixes in image 7. We installed image 7 and are ready to create a selective package with the required bug fixes. In defining the package should we (a) use demo as target then apply package to development and test; or (b) use development as target then apply package to test.