The Straggler and me are known as Lanterne Rouge riders, we could be quicker if we want to or need to recover time for a mechanical or headwind, but generally our approach is to only use 80% effort, start at the back, and reach busy controls as others are leaving, saving waiting time.
I tend to set the time targets between controls, this keeps our pace consistent and buys the stopping time, which we use as we wish, sometimes 20 minutes, sometimes 40, even going into the red if we know we can buy it back on the next section. So really we do what many do, treat a long distance ride as a series of short ones, taking whatever stops are needed, eating what you can, I am down to milkshakes after 200k or cola to soothe my throat.
For us this allows for an enjoyable ride, we finish fresh and well within time limits as a rule.