Here is what we'll be building:
Step 2: Trim and Drill and Awl
Step 3: Get Strapped
Pictured below are the drilled/trimmed buckets, the assembled carry strap, and the assembled bungee retaining strap. Shock, aka Bungee, cord is inexpensive so I bought new at approximate 2' lengths. Overkill... better than underkill. Really we only need about 18-20 inches.
Use your best judgment for the measurement of the webbing straps.