Fore/aft position of different saddles

[macaroon]

I don't know if this has been done before, and it's potentially a silly question, but...

Do certain saddles necessitate a setback seatpost, or an inline seatpost?

Have you found when you've swapped to a different brand of saddle, you've had to buy a setback seatpost, or a inline seatpost, to put the saddle in a more comfortable position?

If so, which brands/models?

[ColonelJLloyd]

It's well known that Brooks saddles, especially the Professional, have a short usable section of rail often necessitating a seatpost with more setback to achieve the same position.

[Lewis Moon]

You can pretty much never go by the nose to (whatever) measurement when swapping saddles. Where the saddle starts to get wider, horizontal profile...lots of dimensions will dictate that you are comfortable in a different place on any new saddle.