I would merge all the pages of the different keys of the song into one PDF, then set up bookmarks to get to the correct key you need quickly as described in a previous post. The Quick Action bar can be configured with a button for the bookmarks window to appear when you tap it. You will be able to go from key to key and they are already in memory to get to quickly (although there are minimal delays generally anyway when you select another song to load).
You can merge on your computer (with suitable software) although you can add to an existing song in the Song Editor, adding the other key PDF.
Settings>Storage>Add unique ID to file names
This means the same file name does not overwrite an existing one (it adds a unique number to each import). I have not tested this extensively, but can confirm it is adding different numbers to everything I have imported so far.
What you want to achieve sounds quite simple, but I would make a backup first just in case, then try it.
You can merge on your computer (with suitable software) although you can add to an existing song in the Song Editor, adding the other key PDF.
Settings>Storage>Add unique ID to file names
This means the same file name does not overwrite an existing one (it adds a unique number to each import). I have not tested this extensively, but can confirm it is adding different numbers to everything I have imported so far.
What you want to achieve sounds quite simple, but I would make a backup first just in case, then try it.