Hey Maternicus,
can you do some detailed photos of the downtube? Especially how slim the downtube is compared to the bottom bracket.
I considered to buy a LCR006-D from LightCarbon cause of the super slim downtube and the low reach compared to stack geometry but they have a MOQ of 50 sets...

I got a frame from them since May 2019.
Nothing to complain till now.