Re-organizing my Google Voice settings

I love Google Voice, and it's been working great, but I've needed to fine tune the settings for a while now.  Here's what they are as of now:

Phones
I have three phones set up (as I suspect most people do): Home, Work and Mobile.

• Only Mobile is "checked" - I believe this makes it the only "default" phone, and therefore, by default, it's the only one that rings when my Google Voice number is called, unless other rules are in play (see "Groups" below).
• All three phones are set up to ring on both weekdays and weekends.
• Home and Work are not set up to directly access my Google Voice mail when calling my Google Voice number - they require hitting the star key during the greeting to access my voice mail.
• Mobile is set up to go directly to Google Voice mail when calling my Google Voice number, but I must enter my PIN to access voice mail.
• Mobile is set up so that when anybody calls my cell phone's number directly and I don't pick up, my other phones will ring before it goes to Google Voice mail.

Voicemail & SMS

I recorded a single voice mail greeting to use for all occasions, instead of the standard Google Voice greeting.

• When anybody leaves a voice mail message, a notification is sent to my e-mail address, and a SMS is sent to my cell phone.
• SMS messages sent to my Google Voice number are forwarded to my e-mail address.
• Google Voice is set up to transcribe all voice mail messages.

Calls

• I have screening turned off.
• I have presentation turned off.
• Google Voice is set to display the caller's phone number on my cell phone when a call comes in, rather my Google Voice number.
• When I SMS another phone from any of my phones, my Google Voice number will be displayed on the recipient's phone.  This really only applies to my cell phone, since that's the only phone I SMS from.

Groups

This is a tricky area, so I did some thinking and came up with the following work flow.  There are three levels of callers to consider:

Level I: Everybody

- People I don't know: should just ring my cell phone

- People I know: depends on the caller.  Can be organized individually or in groups

Level II: People I know

- People not in groups: should just ring my cell phone

- People in groups: depends on the group, but generally should just ring my cell phone

Level III: People in groups

- Family and Friends: should ring cell and home

- Work, Coworkers: should ring cell and work

Exceptions can be applied on an individual basis, but some experimentation should be done when I get the time.  For example, if I set up an individual to have specific settings, but then subsequently change the settings for the group that individual belongs to something different, does that wipe out that user's individual settings?  In most cases, I think I'd like to keep individual settings unchanged, but on the other hand, changing or re-applying group settings might be a great way to "clean up" a lot of individual exceptions.  This brings up a related question - suppose an individual belongs to two groups, with different settings?  Which group's settings apply to this individual?