I would say try the same as last time (390?) and focus on doing it with perfectly controlled form.
Ive only been training a year, but have found the relation between grip and sucessful pulls to be highly neurological.
After I finally got starting strength recently, I noticed Rip also mentions that the back just plain refuses to allow what the hands cannot support.
And supporting weights with hands is a lot about being used to gripping hard. Your hands could be technically strong enough to hold the weight, but the unsureness due to lack of practice would be enough to screw up your grip and neurological connection to the rest of your body allowing the lift.
In short, Im saying do a warm up set. After this your ability to grip will be re-kindled and you can judge realistically how much more weight you can pull.