You can shoot it either way. There's a thread on Brian Enos you might read. If you feel comfortable sitting you MIGHT save a fraction of a second.
Key items are: it's Comstock so you can shoot makeups (which slow you down) and a no-shoot and /or Mike kills the stage for you. Lastly, you're very rarely restricted to head shots at USPSA so there's psychological aspect present.
Make sure you have the latest info on 09-07. The 53" distance for T1 & T3 is from the edge of T2, not the centerline. There's a clarification on the USPSA website.