Phoned Brands Hatch to find out what time testing starts tomorrow, and turns out they are running 4x classes (CaterhamA, CaterhamB, Single Seaters, & Others), each of 25 minutes. That means my morning testing will be just 2x sessions of 25 minutes (assuming no stoppages/red flags).
On the plus side, not many corners to worry about. Time to search YouTube for some help.