2Lambie standard straps (without rPFAs) measure 15" down the middle. We have found that our straps (tightened all the way) fit like 12" when compared to other onbuhimo designs. The 2Lambie onbuhimo panel design has a dramatic curve from the top of the backrest to the outside edge of the shoulder. Many other onbuhimos on the market have a much flatter panel design at the shoulder joint. Therefore, if you measure from the inside edge of the shoulder (shown by the black pen in the photo) you must subtract 1.5". In addition, the straps can be tightened all the way to the ladder locks , which are inset 1.5" from the bottom of the strap (visualized by white card edge to the right of the ladder lock photo).
The 2Lambie webbing is 1.5" wide, which we've found to be more comfortable going under the arm than the typical 3/4" webbing that is more common in the industry.
We have found that this strap length fits a great many people. But some people will prefer a shorter or longer length strap. Custom strap lengths as well as rPFAs (Reverse Perfect Fit Adjusters) are available on custom 2Lambies.
If you have specific fit questions please IM me through Facebook.