I have a 2002 Raleigh SC Tandem, which uses 29.2 mm seatposts. I may need to get a different stoker stem, but looking around at my options, it appears that this is a non-standard seatpost diameter and that 29.8 is the closest "standard" diameter for a tandem. What are my options? The size differential seems just small enough that a shim may not be practical and just big enough to make me worry about trying to just tighten the clamp down a little extra. It may depend on the clamp mechanism. The difference in circumfrence would be 1.9 mm by my calculation. It doesn't seem out of the question for a clamp to have a gap at least that big.