My digital bathroom scales refused to measure each piece individually, but the ADM, saddle blocks, Top vixen and three rear spacer rings came to 1.7Kg. If I removed the rings from the scale, it became 1.2Kg. See pic of the items. YMMV with scales
FYI possibly, the spacing from the rear flange of the RC to my QHY9 CCD plane is approx 25Cm as shown in the pics below. I also needed a small 1.25Kg dumbbell front weight to keep things happy. See bolted under ADM in pic.
I use a Meade microfocusser + FCUSB and so clamp the GSO Crayford down tight and it never moves until I change cameras. Suits my rough and ready style....
My apologies if overdosing you.