As a technical founder who is always surrounded by non-technical people, this is what I would personally look for.
1. Traction - as others have mentioned, traction is king (whether it be with investors, users, paying customers, or ideally all of the above). We want to know that we are joining something that is already moving at a fast pace and that we're coming in to help accelerate that / bring it to the next stage; not something that could potentially go somewhere if only there was someone to help it start. Ideas are pitched every day that are nothing more than theory and finger in the wind predictions so having something to show will really differentiate you from others. Sounds like you're already working towards this with the prototype and 200 early adopters so that is good.
2. Skillset / Experience - non techies need a CTO to code up the product. In return, show the techies why they need you. A truly compelling scenario would be one that the potential CTO can see that you have everything non-technical covered. Separating roles (e.g. the non-tech does 'sales & marketing, fundraising') is not enough, you need to show why you are an expert in those fields beyond any other non-technical founder we've talked to (e.g. you have a very specific 'in' with the market you're targeting, you've got 10 investors lined up to invest when the prototype is ready, you have hundreds of thousands of followers on <social media platform>). If we see that everything else is firing on all cylinders except the tech, then we can focus 100% on that and not have to question / worry about the rest.
3. A Compelling Story / Plan - beyond and perhaps even before telling us the actual product you're trying to create, sell us on why it is so desperately needed in the first place. Build a high level narrative around the problems that exist and why current solutions don't work, and then go into the specific solution you came up with. While we may be narrowly focused in building a single product, we also want to know where it fits in the grander scheme and how it will impact the world. Similarly, show a well thought out plan on the various stages of the company and how that will lead to inevitable success, with a large focus on the concurrent technical / non-technical timelines and how they fit together. You'll have to proactively fight the unfair (but perhaps not unfounded) perception that the non-technical guy will sit around twiddling their thumbs while we pour nights and weekends into building a product, and then get to work once it is done.
Lastly, don't position the technical work as just stuff that needs to get done so <more interesting next step> can happen. This interestingly happens quite often (e.g. "All I need is a simple iPhone app that sends messages and we'll be the next Twitter!"). It downplays our contribution to the overall company and shows naivety in how much actual work is required on all fronts for a startup to succeed.
In summary, make it apparent to the potential CTO that you've got everything not only figured out, but working in practice. Show that the technical product is just one piece of the equation and everything else is already in place, and they can rely on you 100% to deliver on all of those items (because you already have).