Should my screensaver or screen lock be de-activated?

Yes, the screensaver (and any automatic lock after a period of inactivity) should be disabled. If this is not possible, the period should be set to as long as possible. You will have to take this period into account, avoiding that the screensaver or screen lock becomes active, because they can create instability and force the lockdown browser to close.

Similarly, power-saving functions should be disabled, such as those which cause the computer to automatically power off, sleep or hibernate.