Primary side connections from one anode to the other:
Grey---anode1
Blue---a1-40%
White---a1-30%
Black---a1-20%
Red---center tap
Black-Red stripe---a2-20%
White-Black stripe---a2-30%
Blue-Yellow stripe---a2-40%
Purple---anode2

Secondary takes output from the green and green/yellow for 8 and 16R. For 8 connect/strap the yellow and yellow/black and for 16 connect the black and black/white stripe. For 4R we put the two halves of the 16R winding in parallel.

They are 10k a-a, and rated for 40W. This is a bit conservative, as they've got 3.4 square inches of M6 core. At ~20W/in^2 they are more like 60W.
cheers,
Douglas