I use DD-X at 1:9 for 10mins 30sec @ 20C. Negs aren't thin as you describe and print G1-2 on condensor enlarger (Durst M601)(posted 8428 days ago)couple of left-field suggestions, developer's off (was it new), your agitation (I said left-field!) or metering are suspect (maybe made a blunder.. have you done this more than once?)