Generally no, once I found an "ideal" foil mast placement for a particular foil setup, I no longer changed that, and when changing the sails I played with the rig's mast foot placement instead. Bigger sails more towards the back, and smaller sails more forward in the track.
But then I discovered there are several ways to achieve the same result. On my board the mast track is very close to the front foot straps, and on such a setup it's actually possible to control how much weight the rig puts to the mast foot by simply leaning the rig forwards or backwards a bit. With the boards that have the mast base further away from the straps the effect is not as big, you would need much bigger sail movement to achieve the same result.
Here are a couple of examples, at first I though that with a light weight 3.0 rig (with a 310 cm super light mast) I needed to move the sail further forward (first clip). But later I discovered an even better setup (2nd clip). I moved the front straps 1 step forward, and after doing so I could use pretty much all sail sizes with the mast base in the same position (further back), and the foil mast in the same place as well.
3.0 m2
3.5 m2, with a much more ideal setup.
4.0 m2, also with a new setup, distance between the front straps and the mast base pretty much as small as the board allows, the 3.0 m2 sail works wonderfully in the same position.
5.6 m2, with a different foil setup, but the same principle applies