The wow website - first thought equine ( fte) explains all the applications of all the variations of each component, but tbh there are so many variations that you really need an experienced fitter to get the best selection for an individual horse.
Yeah I've read that over and over, can get my head around all of it except the tabs, have a welshie with a bit of wither but not huge - have the fitter booked in a few weeks but pretty sure I need new panels, found some with no tabs but just a bit twitchy about pressing the pay button :/
On horses with a wide square shape backbone at the wither, the panel with no tabs can dig into the sides of the wither at the top corner. The same panel with tabs sits wider at the very top. My first set of panels the had to be changed for that reason.
If you open the panel (they are Velcro fastened) you will see that all they have done on a tabbed panel is bend the corner of the airbag down and stick it in place! In theory, if anyone has a non tabbed panel that doesn't fit, they could easily change it with a bit of strong double sided tape