It makes sense to inform the list of your proposed developments and discuss the approach to be used. There are some knowledgeable people on the list and they can contribute ideas if you let them. Alternatively, there is a section on the webERP forum for posting development specifications for what you propose to do. This is also good to avoid overlapping effort or combine efforts in working on different elements of the same project.
Obtain the latest development scripts from github - there is a nice explanation of the workflow on the github webERP wiki describing how the development process goes.
IMPORTANT: Only do development work on the most recent scripts from github and update your fork regularly.