Rear cinch sizing

Hi,
Horse is 14.2hh Arab-QH-X and petitely built. We use a 15" western saddle with a 30" girth. Looking to buy a rear cinch. I don’t know the appropriate length to buy. It seems like the market tends to sell 36" rear cinches with 20" billets and the connector strap. But would that be too long for her? I know the rear cinch will be a little longer but I do not know by how much…

Thanks!

Just to give you an idea, my back billets are 26" long with a 34" cinch. I ride a lot colts and smaller horses (13.3-14.2) with the back cinch fitting fine but it’s still long enough for the bigger horses I ride. I have never needed to punch holes or change anything.

Standard size should be just fine

Alrighty made the purchase. Thanks!