There is no danger if you follow a reasonable procedure. Create a new area in your disk structure for the OE10, install Progress, restore a copy of the database to a new location, convert the DB to 10, do what you want with the DB in terms of changing to Type 2 storage areas, etc., copy your source to a new location, compile that source into a new location of the OE10 R code, and test. This will be completely separate from your production system ... could even be on a totally separate machine. No danger, Complete control. Just good practice and you can test to your heart's content, figure out what you need to know, practice the DB changes for timing and technique, etc.
If you need even more security, involve a consultant to guide you through the process, but really this is all very straightforwarrd.