>>50394
You could do a slight negative split like target 390-395 for the first half and then ramp it up to targeting 405+ in the second half, that's how I do all 15+ minutes max efforts and it works very well for me although keep in mind the lower you go the more you need to ramp.
There's something about being in control and knowing you have more in the tank, if you make it through the first half feeling alright a lot of the doubt is gone and if you make it through the first half feeling bad and on the limit you know you never had more in the tank in the first place and the goal was unattainable.
But this shouldn't be a question of whether you can do it or not because you know you can, you know your numbers so you simply do it.