How to level an uneven subfloor before laying solid

[ianmorrison]

My subfloor is a concrete slab which had floorboards ontop of it, i have plugged and screwed down the existing fb to the slab so this is rigid now, no movement at all. The floor is fairly level however there are a few ridges and high/low areas which i am concerned about as i am laying solidwood flooring. I want to prepare my floor as accurately and professionaly as possible becauce i am do not want my new flooring to creak or to look god damn awful.
What options are available to me and also the flooring is running from my hallway into the lounge, but how do i finish the flooring at the front door, is there an end piece you can buy with a bull nose etc

 

[WoodYouLike]

I want to prepare my floor as accurately and professionaly as possible becauce i am do not want my new flooring to creak or to look god damn awful.

Screwing original floorboards onto a concrete floor to stop the creaking or moving is not the best of ideas to be honest. Wood works, we've seen whole floorboards split because of the screws obstructing the normal movement during the different seasons.