How to measure wrist for an Apple Watch Alpine Loop Band?

Oooking to buy an ultra 2 with the alpine loop, wrist seems to fit into all going by listed size.

tried one in a local store, not Apple Store as it’s miles away. Seems to fit fine but because of the security tags they can’t take the strap off to check the size, and they “don’t know the size”. Counter the loops and I get 29. Anyone know what size that is in the options of small, medium and large bands?

thanks

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