You certainly don't need the additional drag to stop and you certainly don't need the possibility of uneven drag from partial spoiler deployment due to the hydraulic failure, no spoilers is the correct procedure in this case.
Doesn't the Center Hydraulic System control symmetrical spoilers?
On the subject of drag, how does the co-efficient of drag of aluminium and composites on a foamed runway compare with braked rubber on a non-foamed runway?