Are you new to detecting, or new to the XLT? If so, I'd change only the bare minimum of factory settings, and leave the rest alone for a little while. Reason is: I was president of a club for many years, back when the Spectrum and XLT first came up (1990s). I can't TELL you how many people came in with their XLT "acting haywire", and seeking advice. Invariably, when I'd look at their machine and their settings, I'd see that they'd gone in there and maxed out every single setting. When I'd ask "why'd you max this and that?", they'd say "because I didn't want to miss out on anything" Doh! I guess they'd hear someone in the meeting comment on how they'd fiddled with this or that, then the newbie would see some nice find those aces had made, and figure he'd better max out everything, lest he be in wimpy beginner settings. Then he'd end up with a spastic sputtering mess.
So start out with the basics, barring just comfortable adjustments on background hum or volume, etc... Once you're familiar with it, and have dug hundreds of targets, then you will have a better appreciation for the various suggested programs/changes you will find on-line.