I want to make everyone aware that we do not use Baltic birch. We have the hardest north American maple top and bottom layers as visible veneers which are available on the market. We have them shipped in from north America and they go through a special hardness test to make sure they are hard enough. We use only A graded quality.
By the way - if top and bottom layer veneers are not in the same thickness the boards will warp. So if there are different thicknesses used or one is sanded too thin and the other is kept at full thickness warping could happen worse than normal.
Regards,
Mirco