Nevermind,
Seems like the solution is already here
I just replaced the standard WaveShare 7 HDMI+USB 1024x600 config in the advanced view with this one.
hdmi_force_hotplug=1
max_usb_current=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 1024 600 60 6 0 0 0
hdmi_drive=1
Edit:
The solution seems to be partial tough:
Touch seems to work only after unpluggin and replugging after boot.