3rd try now for my part, still no success:
increased exposure time to 6 and 8 sec, still horizontal lines, printed only the external shell without any internal features, still horizontal lines.
It’s been more than a month now and still i cannot print a medium sized part without defects.
Hope the Teflon AF solution will come to market, might be a solution for my problems. Still too much time spent troubleshooting and not enough designing and printing.