Subscription Choice Before Checkout

Hello. We're a portuguese brand that will have a period of rebranding in July. And we have a build your own box page, and in a separate area we have a subscription plan option. This separation has different problems for our clients: - Our clients have to create two different accounts: one for the online store and the second account for the app of subscriptions plans; - The app is not user friendly; - We have some trouble in the backoffice of the app. So, for the new fase of the brand and with the inclusion of new products we want to have a easy solution for subscription: once a person goes to checkout and adds the products to the cart they can chose if it's a normal order or if they want to subscribe monthly. In the image that we attached you can see an example of this dynamic that we want to include in our store. But we don't have a limit of snacks, this thing can be unlimited (we've have only a minimium quantity of 10 snacks to order in our online store). I will give you some more information that can be useful: 1. The link for our build box page: [login to view URL] 2. The app we are using for subscription plan: Paywhirl 3. Topics that we can also view resolve: - The importation of the actual clients that have a subscription plan to this new dynamic; - We don't need apps to this integration, for not to overload the website; - We want to have some discount codes that a person can use to the subscriptions order only (like 10% discount, etc). - Dynamic discounts: the more a person takes the more discount they receive (only in subscriptions). 4. The person can consult they subscription in their shopify's account and do changes to the items everytime they wish. So, our idea is right before a person advances to checkout they can choose to buy one-time they mix of snacks or they can chose to subscribe that box monthly (or buy a period of days). I also attached a image of our pre-checkout area were we can put this choice for the person. What do we need to know: - For doing this, you can only work when the website is all set-up and for that we need to know how many time it will take (for we can keep the website off) and also agree on a day to do this.