What a beautiful set up for your bike transport! I admire its elegance.
My husband and I looked for quite a while for the right van for our semi-recumbent e-bikes. These bikes are somewhat long, with high handlebars and wide seats, so finding something to fit them was a challenge. Wanting something that would hold the bike securely but not weigh too much led us to make the bike racks shown in the attached photos out of PVC. It just takes 1 or 2 bungees from the top (we put stainless steel eye bolts into the threaded holes).
Yesterday was our first day trip with the bikes and it went just as we wanted: safe bike transportation with the ability to stop along the way without the worry of the e-bikes being damaged or stolen.
Thanks for the many useful ideas from the members of this forum.