Takes more work than that - look at how normal scripts in /etc/event.d/ are worded - they have lines stating when the script is to be executed and/or stopped. (Hence why it's "event.d" - it's a directory for scripts that are ran on a specific event.)

So you'd have to add that to the load.sh script.

Also, keep in mind, in my experience running the bleeding edge drivers causes spontaneous reboots when connecting to an ad-hoc wireless network. So you'll be in for a jarring reminder of that if you forget after setting your N900's default driver to the bleeding edge one, and then go to connect to an ad-hoc network.