As a supportive Festoolian, I must say this up front ... "You NEED both".
Now that that's out of the way.
If you intend to mark the required height, then remove the door for cutting, probably the TS. If you are going the trim-trial-trim-trial .... path, then it's the planer (EHL65 is perfect for this).
Keep in mind that if you desire a OF2200 router, you can use a track and trim a whisker off the door as well
![Big Grin [big grin]](https://www.festoolownersgroup.com/Smileys/default/biggrin.gif)
For very fine final adjustment, you will certainly need a RO90 and a range of grits !!!
That's only 4 options - with 7 doors, there's another 3 Festool potentials to consider.