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.

I will post a schematic to projects as soon as I can visit a scanner.

Several inquiries made regarding the grid chokes. The Heyboer PN is HTS-7457. Specify a .002" gap of Nomex paper. Even though there is no DC, the gap is useful.

With this 10kOhm a-a OPTx, if you want to run an AB1 bias, draw the load line at ~2k5 as you would for SE, with a single set of plate curves. If you're staying Class A, draw the load line at 5k. Any of the three pairs of taps can be used for g2 connections. The E-Linear tap does noy have to be the same pair. Of course, class A U-L curves are not generally available...:(

Looking forward to seeing a few of these amps come together.
cheers,
Douglas