How is it .....

[jameso]

When I had my ti frame made I went for the usual large diameter seat tube (as you would for a strong, exped capable bike) and for flex I can insert a sleeve and thin eg 27.2 mm seatpost... did the same to two rigid steel frames.

This is the way to do it. I've had 3 shimmed Ti frames, all good. First 2 were Genesis Ti. 27.2 ID seat tubes on an MTB now make zero sense to me, esp. in Ti which needs the larger ODs for some stiffness.

[Johnallan]

I've just put a deposit on a Fairlight Holt which apparently has a 27.2 seatpost and I've added a dropper to the order. Never owned a dropper before, nor paid any attention to seatpost diameters. Just a tube innit?

[Alpinum]

We better call Chiru and tell them how to design a proper specific frame.

[Alpinum]

I've just put a deposit on a Fairlight Holt which apparently has a 27.2 seatpost and I've added a dropper to the order. Never owned a dropper before, nor paid any attention to seatpost diameters. Just a tube innit?

Yeah. Kind of. It's two tubes and some lego bricks.
If you buy Fox Transfer it's two tubes and metal parts.