I can vouch for the idea of delaying the contractions. Previously, my PB was just over 5:00 with contractions starting like clockwork at 2:30. This was frustrating :vangry when I knew others never got them at all.
After reading some comments in here, I realized that it's possible to consciously delay the contractions. I was surprised by how much it helped: trying to delay them on an incremental warmup (like the O2 tables) immediately enabled me to delay them until after 4:30, making a 6 min static possible.
Instead of caving in to the temptation of the first contraction, I allow a "welling up" of internal pressure instead. At some point, the pressure feels enough, and I allow it to start. Once they've started, I let them happen unrestrained. :mute
However, I still haven't figured out the best way to reduce the amount of time needed to get to the "warmed up" state...
Good luck!