I wish the specs were more clear also. It's a high-end bike, customers will want to know exactly what they're buying, especially as more competing offers come to the market.
Keep in mind, that if you go from one frme to another with a difference STA, the required toptube+stem length reach also changes. One degree slacker in the STA has you require a half inch more in the top tube. Whatever your STA is after all, the adjustment range in seatposts and seat make that the seat will end up right where you want it anyway. Only after that does one (normally) pick a stem size.
Keep in mind, that if you go from one frme to another with a difference STA, the required toptube+stem length reach also changes. One degree slacker in the STA has you require a half inch more in the top tube. Whatever your STA is after all, the adjustment range in seatposts and seat make that the seat will end up right where you want it anyway. Only after that does one (normally) pick a stem size.