Hi,
this project is very interesting for me in two reasons:
1. The explanation of what do you need is very good.
2. Yo required all function to be build from scratch.
For requirements like this I prefer to use GUI solution.
So, in case that I am working on this project, it will be performed in 3 steps:
Step 1. Make GUI and worksheet layout. Functions will not be provided. Provide pdf file with explanation how to use app. When we agree about how app should works (the function of buttons, how graphs should look like...etc), we will go to Step 2.
Step 2. Make application and test it. Send app to you.
Step 3. You will perform app test. If you find some bugs or want to make some little modification, it can be solved/done in this step.
Time schedule will be:
Step 1. One day
Step 2. Two days.
Step 3. One day.
I always commented out my code, explain every function, variable...Also, I provide user with user guide for app which have GUI. And more important, if you find out some problem in the future, you can always contact me via chat, and I will try to help you.
You can check review from millwooddl about how my code look like.
For any additional questions, feel free to contact me via chat.
BR,
Alex