patching concrete floor before laying oak

[woowoospanner]

I'm 90% of the way through flooring my dining/lounge room but have come across 2 patches where the fireplaces have been that need filling to bring up to the level of the rest of the floor .

what should i use ? cement based leveling compound (just add water type)

How long should i leave it before laying the wood floor over ? its going to be about .5 inch thick .

Thanks in advance

Derek