My general strategy has changed on this:
To start with I went into the LEL with a complex spreadsheet plan A & plan B. After the first night unable to sleep when my plans both said I should
I decided to ignore it & just look at time in hand according to my brevet
Then on WCW I got caught out looking at the control times on my brevet - they were calculated to an over-distance route, but the finish time was strict BRM... I didn't notice until there were only 2-3 controls left and had it not been for a stonking tailwind at the end I'd have been way out of time...
So now on long rides I simply take a note of the 'real' closing times for my start time & the route (i.e taking into account the total distance and hard time of the last control) - I then strive to make sure I leave any given control within that time limit.
I realised on the BoB ride last year that I could even find peace with being over those limits. I knew that the end of the ride was flat, I went almost 4 hours over the intermediate control closing times but finished with nearly 2 hours to spare
Sure, I would have liked not to be so far over time in the middle, but I simply couldn't do any better due to indecent, my legs & those hills (i figured I'd only stop if they told me I was out of time)
So for PBP - I'll check my control closing times, strive to stick with them, but if they start to slip past will just keep the faffing down to as little as possible & try to keep moving as much as possible.