Mounting hydraulic clutch master cylinder question

[scherp69]

I was just looking at this thread http://www.pro-touring.com/forum/showthread.php?t=55585 about the DSE clutch master cylinder bracket from DSE. I've never installed a hydraulic master cylinder and am close to being ready to prime my firewall. I'm leaning towards using a Wilwood master so it matches the Wilwood brake master that I have. Before I lay the primer on, do I need to get one of these plates to install a hydraulic master cylinder or will the existing hole in my firewall work? Here's a pic of my firewall.