Hi Mugre;

Should not be a problem; as long as you do not have too much seat post above the frame.

We're running a shim for the stoker, with no issues.

Note: strength of a seat post is proportional to the seat post diameter to the fourth power. (a 30.2mm seat post is twice as strong as 25.4mm seat post - same material and wall thickness for both). Stress on a seat post is highest where it meets the frame and is proportional to the distance from the frame to the center of mass of the load on the saddle.

I hope that you are enjoying your T50 as much as we enjoy ours.