Seven Redsky seatpost size question

[DavidMtl]

I Just bought a used Seven Redsky.

The seatpost (not a Seven) is 30.9mm with a shim. Without the use of a shim it would needs a 31.6mm seatpost.

I am wondering if the frame was intended to have that setup (30.9mm with a shim) since, on their website, Seven offer their home brand seatpost in either 27.2mm or 30.9mm only.

I need to change the seatpost to have one with more setback so I'm wondering what size to look for 30.9mm or 31.6mm.

The 100mm long shim make it look not to bad so if there is no disadvantage to it I may continu using it with a 30.9mm.

Any thoughts about that?

Thanks a lot!