But I realised that all the strength would be on the angle brackets and the screws. So I made a new design where the two main wooden beams are laid on the four vertical beams. It reduced the number of 3m wooden beams by two because instead of having 4x2m beams I had 4x1.4m beams.
I made some tests and saw that the main wooden beams could support about 1000kg but the slates could only support about 50kg. With the help of the bed, the weigh should spread on the other slates but I still would like to have your opinions.