Follow-up:
My Aerocreeper was delivered yesterday. Arrived fully assembled and securely packaged 53lb, 24"X57"X8" cardboard box. The creeper is sturdy and heavy, and I'm very happy with the quality. I only have one squawk...
The bolt threads that support the seat-back adjustment carriage are pointed inward towards the seat-back upholstery (see photos). The gap between the bolt threads and the seat-back upholstery was too-close for my comfort. Although there is no side-to-side play in the seat-back frame at all, I now feel more at ease having reversed the bolts - threads now pointing outward from the creeper. This created more room between the bolt head, and the seat-back upholstery.
That's it - only squawk I have. I'm very happy with the purchase!