Hey man 
Have a look at this post.
On STRUGGLING TO DECIDE about your DB format… I think just Develop quickly, have fun playing in the editor which will also improve your fluency in the system… That way you can launch quickly, make mistakes quickly and change quickly. Remember, this platform is SUPER efficient in that we can implement changes super quickly. So I vote for just having an idea, make it happen bro and worry about optimizing in the future. Sketch, Launch, Optimize, repeat!
On INDEXING: Have a boo at this post: Creating a data field dynamically
Indexing is THE BEST way to quickly improve the speed and efficiency of your DB’s performance.
On LISTS: I’d argue that leveraging LISTS is the second best step to optimize your performance… That is to say, your clients can be playing in your creation and interacting with your data quickly when changes are made to a STATE STORED LIST, rather than the clunky updating to a DATABASE and waiting for those values to come back to you. Of course you need to manage your data carefully, by divorcing, yet monitoring the flow of data… (ie. when do you push updates to your DB?).
Finally, I encourage you to just follow the idea that you’re having… ABC & D… make it, move on to creating other features… and when you discover that your solution is deficient in some way, drop me a line and I’d gladly SKYPE/HELP you optimize your shiznit
Peace bro!