Built 2 sets concurrently and just hung with the first completed set last night (worked great!). Here are some things I learned from the process:

Order your snaps and pliers right from Kamsnaps.com. Their prices are better than Amazon, their selection is awesome and you can get exactly what you need for the project, and they support canine rescue with the proceeds of their business.

On the snap diagram for "Castor", the side facing up will become the inside of the top quilt. Minor detail, but important if your OCD (like mine) requires the outward sides of Castor and Pollux to match when in summer mode, you need to put the inner color of Pollux as the "This Side Up" side of Castor when you install the snaps. Pollux would technically be reversible except I added side loops to attach to my tie-out guy lines to secure the underquilt.

This is another OCD touch for me, but I used "pronged studs" on Castor's ends so that the grosgrain loop around the nettles would be closed when the two are stacked. It also gives you an option to overlap the outermost fold in top-quilt-mode to further reduce air gaps.

Attachment 182317