Hi Matt,
Cool installation 
It is possible to daisy-chain the Micro Maestro, I have done it on the robot I am currently building. I am only using two, but 7 should be no problem according to the documentation.
I have written some Arduino code to use the Micro Maestro that you can find in this other post. Just copy the code into a .pde next to your main sketch file, set the serial parameters to match your installation and you should be good to go.
Also, you can have a look at here for complete documentation on daisy-chaining the Micro Maestro.
– Xevel