Your drive is a oem drive, so you have to use the firmware thats starts with the letter G, a bit lower on the page you mentioned, you''ll find firmware G7P9. This is the latest firmware for the oem drive.
Which do I grab and how do I use them?
If you don't want to void warranty of your drive, you'll have to stick with firmware G7P9. It's a very good firmware and some people prefer G7P9/B7P9 over the B7T9., I think it's a matter of personal experiences with dfferent media.
What role does winddwflash.exe play in this? Do I even need that?
If you want to convert your oem drive to a retail drive so you can use the firmware that starts with the letter B, than you have to crossflash your drive by using firmware as a *.cvt file. When you stick with the G firmware, their's no need to use the WinDWFlash tool.
Guess I am in need of handholding through this process for the first time.[/QUOTE]
Better ask some things first than to do stupid things you will regret later.
My advise to you would be, use firmware G7P9. Burn some disks first. Post a few scans. Ensure yourself that your drive is working fine.
Firmware G7P9 is a good firmware, don't go flashing when their's no need to (right now).
Do some reading here on the forum. Take a look at some older threads, you'll learn a lot by reading them. Later...when you decided you want to flash your drive with the retail firmware, you'll probably don't need our help anymore.