I like it when a plan comes together!
The tw523 has no memory. It is the module itself that remembers the on/off & the dim/bright levels. It's-good to know that the way to use dim/bright should be used with 1 repeat. By the way the older x10 modules do not have the ability to transmit so you cannot read from them. It's probably a good idea to have a spare tw523 on hand.
Good for you for sticking with your project!
PS
I made a micro chip controller x10 receiver that has 32 relays (2 house codes) works great! 1-16 are on/off and 17-32 are momentary on.