Please clarify mechanics for new Polarity Shift

Can we please get clarification about how the new Polarity Shift will work? Here is my specific concern. What if the board does not provide the opportunity to create a match-3 by placing three tiles, but can allow you to set up a match-5 by moving one of the tiles you place. Will the reds that get generated replace any of the existing blues? For example:

enemystrike.pngbluetile.pngbluetile.pngtutile.pngbluetile.pngbluetile.pngprotect.png

since you only get three blues with the new PS. I would put a blue above or below the TU tile so that I could use my turn to create the match-5. With the new capability is that a safe move or would I end up wasting the placements?

A similar scenario to this would be having to use your turn after placement in order to create a match-4 that allows you to eliminate an enemy CD tile. I know PS is used primarily for AP generation, but I have often used it to remove pesky tiles that are otherwise impossible to get.

Further, will the reds that are spawned replace only standard tiles?

Thanks