Design and approach advice on module development

Hello everyone, i'm rather new here to the openerp community and glad to take part of it.I have been recently tackling with a project and thought of many ways to go down but openERP seemed the best way.I'm going to post the projects specifications and my progress so far, any help regarding any topic will be greatly appreciated :)

https://docs.google.com/document/pub?id=12Ugl9X2aNtRP2Nbj9-bcr_WBrvdV8p_LlXmlCpZvbYs

Thanks for anyone's time and patience of going over that and maybe even providing some feedback, cheers!