What are the implications of the whitespace and hidden characters option for our projects?

Question

It seems to me to be the whitespace and hidden characters (WHC) option will significantly impact our projects. It provides some real benefits but also has the potential to be abused if it is used for formatting purposes. It will require some careful thought to make sure we use it well.

[Editied] See John Wickberg's answer in the related post that earlier versions will remove some whitespace characters.

I would like to know exactly why it was necessary to make a project incompatible with earlier versions when WHC is enabled. I have some ideas but would like to have them confirmed and/or corrected:

• The tilde character. In earlier versions of PT tilde ~ is reserved for a No Break Space (NBSP). In 9.5+ tilde is now a normal character. to enter a NBSP you can use the hidden characters menu or type 00A0 CTRL-X
• Earlier versions of Paratext treat whitespaces differently by combining them or converting them to other characters. 

What are best practices when creating new projects or enabling WHC?

• I see that the advice (for now?) is to only make a project WHC enabled when the project needs it, presumably only in complex scripts. I expect that  eventually all projects will use the new white space approach. Eventually I expect WHC enabled will be the default for new projects.
• What should we do with tildes in our projects? They are not automatically converted to 00A0, and they still disappear in preview view. I assume they should not.
• I do know that word separation characters.are not automatically converted to 200B
• I see that the no-break spaces methods under the Project>Advanced Menu have not been changed. Perhaps when a project has been opted in they need to have the methods Replace tildes with no-break spaces u00A0 (NBSP) and Replace wordbreak characters with Zero Width Spaces u200B (ZWSP). Or it may be a good idea to have them automatically converted to u00A0 when the project is WHC enabled.

I am interested to hear others comments and observations and perhaps hear back from the developers.