The preparation of a mould is more than adding kiln wash to it. You need to start with smoothing the mould itself. You can do this by wrapping very fine wet and dry sandpaper round a flexible sanding block. You can use this wet or dry, although wet is more healthy. When you get the surface texture you want on the mould you can let the mould dry or immeidately apply kiln wash. When the wash is dry you can again sand the kiln wash but dry only this time and very lightly. If you sand throgh to the mould surface, simply re-kilnwash the mould again and start over.
The glass will always take up the mould texture, so take time to prepare the mould.
If you really do not want mould marks, do an apature drop and cut off the rim. There is no mould contact, so the glass retain the surface it had in fusing.