The project continues to move forward, although a bit slower than I'd hoped. Looks like one more round of small changes and I'll have the first production tent body ready for usage and be ready to have a batch of these made shortly after.
From the prototype, you'll notice the windows have changed. They are much larger, have internal flaps and flapped in a way that they can be partially opened and still keep rain out. The bigger side windows provide enough ventilation that I've removed the window at the foot end of the tent.
The main tent body will be made from a premium grade 10.1 oz Army duck canvas. This is an extremely water resistant fabric that breaths well, is mildew resistance and does not wick if touched when raining.
For the technically inclined, the fabric is a Sunforger boat-shrunk marine-finish duck. This canvas is a double-fill material made up of two yarns twisted together in a durable "one-up, one-down" construction. It has over 100 tough little double-fill threads per square inch, resulting in a very tight uniform weave that is naturally water resistant. For extra insurance against water intrusion, the canvas is double-dipped in a Sunforger silicone treatment. You can't feel this treatment, it's integral to the fabric — not simply applied to the surface. This "dry-finish" treatment is extremely durable, lasting up to decades. It also makes the canvas mildew resistant.
To save weight and because breathability isn't as important here, I'm looking at a high-grade, UV-resistant coated nylon oxford cloth for the changing room.
Still working on costing, but so far it's looking like the lower end of my original estimates. Once I get the first production unit I'll have full detailed photos/info available and folks close to the Salem,OR area will be welcome to come by and see it in person.