I would agree with Flight Detent.
Vref 40+30 kts would equate to about 170 kts at the most. If you use about Autobrakes 2 you'd use about 2700 m of runway. No big deal. Max Autobrakes would use about 1500 m if you really felt the need. This would probably blow your fuse plugs though.
It's funny how we feel absolutely comfortable flying away from the ground with only Flaps 5, yet flying towards the ground with anything less than Flap 30 is such a big deal!