So I've laid some parquet tiles, I cleaned them before laying so its all clean. There are gaps between the tiles no greater than 2-3mm and some of the heights of the tiles are about 1-2 mm out. Now, shall I fill these now then sand everything down. If so how much do you fill the gaps, as in how much filler do you put down the gaps? Also how flat does the surface have to be once sanded. Its a Maple floor so is really hard to sand. Will be using Bona HD Traffic after so will this get rid of some of the differing levels? Many Thanks