Avoiding "Split Personality Disorder" with Multiple WAPs

Question

For years I have created roaming networks by connecting multiple Airport Expresses via ethernet back to the router, then setting each of them up identically, "Create a Wireless Network" with identical SSID and password, using automatic radio mode, and Bridge mode. 
This seems to have worked quite well, except as you wander with wireless clients they often seem to cling to the original distant WAP before jumping to a much closer one, resulting in abysmal transmit rates.  In fact the only way I can get them to transfer to the nearer WAP is to toggle Airport on and off and that's a pain.
Today I called AppleCare and received completely different instructions.  Instead of setting up Airport Express manually, use Airport Utility's Configuration Assistant and instead of "Create a wireless network," choose "Join a network" then choose connect by ethernet.  They said this only works if you pair up with an Airport Extreme which is set up as a router and in my case they told me to set up an Airport Extreme with "Share a public IP address" rather than bridge mode and to ignore the double NAT and everything would be fine.
I was told that setting up my old way would result in competing WAPs that would create problems as I was experiencing whereas setting up with "join" via the assistant is the only way to create a truly meshed roaming network.
Today as a test I set up a new Airport Express in the recommended way via the Configuration Assistant, and it seems to work.  Yet when I go in manually to examine the settings, they look identical to what I've been doing manually for years.  Not sure if there are other setting differences I can't see.
Here's what I'm trying to do:  I have a Qwest integrated modem/router which is currently doing the routing but I'm not using it as a WAP.
I want to have two Airport devices to create a WiFi network.  Both will be connected to the Qwest modem/router by ethernet.
But I want iPads and MacBook Airs to move easily between two areas of a large residence-- for live video streaming I require excellent transmit rates continuously.  And I don't want the clients to linger onto a weak signal.
Any suggestions?  Thank you.

Answer 1

Although not consistent with my experience, AppleCare told me today the only correct way to use two or more WAPs is that ONE of them MUST be an Airport Extreme and it cannot be in Bridge Mode, it must be in router mode, ie, Share a public IP address.
Sorry, but this is just not correct.
I already have an integrated modem/router from Qwest so AppleCare told me to ignore the Double NAT.
No reason to run a Double NAT, which can cause network errors and slow down the network due to a dual firewall setup,  unless there are no alternatives.
They said to  set the Airport Extreme be the router, and check the box saying Allow this network to be extended.
Unfortunately, they are wrong again, if you are connecting all of the AirPorts using Ethernet. You only need to check the "allow this network..." box if you are planning to connect another AirPort using wireless only......not Ethernet.
Setting up all of the access points in Bridge Mode to "create a wireless network" using the same wireless network name, security and password is a proven way to extend a network. It works perfectly for me, the relatives and neighbors who have done the same thing. This type of network will run circles around a network using wireless only to connect the different access points.
Apple's instrucitons in their document assume that you are connecting the "main" router to a simple modem that does not supply DHCP and NAT functions. It is unfortortunate that Apple did not include instrucitions to connect to a modem/router since that is what 90% of users have.