I want to add a Thomson seatpost to my bike, but it's got a non-standard 30.4 size. Anyone have experience using seatpost shims? Thomson doesn't make a 30.4 (according to their website), but Cane Creek (pic attached) makes a shim that will convert a 27.2 to a 30.4 Will it work OK or should I try and find another brand in 30.4?