I've been kind of watching this project pan out and commend you on your energy to see it through this far David. I feel compelled to share my commercial opinion.
I run a small business, we've been operating for 17 years. We have launched loads of new products in our range. Some successful, some not so much.
What I can tell you is that it matters little as to how well refined the product is or how close it is to a detailed complicated specification when you are budget constrained. It matters more that the product is delivered. And it matters most WHEN the product is delivered. For that reason you should proceed with your first model and get it to market. It doesn't matter if it gets superseded. That just creates history for the lineage. You can fix things as you go, and you know you will have to anyway.
You will never please everyone, and often the noise from the people in the community outstrips the thoughts of the people who will immediately buy the product. The majority of the caucus may not be the majority if the buying public. Trust your instincts, it's the only way you won't regret decisions you make.
Whatever we you decide, best of luck!