to throw some more information into an already fragmented thread...
if billy (enthalpystudios) or anyone else wants to try to wind their own 1:3.5 OPT for the g1176, here's a simplified version of the b11148:
the core is 46 pieces of 29ga M6 steel, interleaved (no gap) in a 0.625" square stack.
the winding structure is:
1/2 secondary
primary
1/2 secondary
first wind 475 turns of 30ga. the beginning is the start of your secondary, the end gets spliced to the beginning of the other half of the secondary.
wind on a layer of mylar insulation
next wind on 270 turns of 26ga. the beginning is the start of your primary, the end is the finish of your primary.
another layer of insulation
finally, another 475 turns of 30ga. the beginning connects to the end of the first winding, and the end is the finish of your secondary.
that's it. try to wind as neatly as possible, or wind very tight randomly, and it should all fit.
have a look at the DIY API output winding threads for details on labelling, bringing out leads, etc.
another good option for a 1:3.5 output is the marinair LO2567 with pri in parallel, sec in series. cj has posted the winding infos.
i'd like to make some full blown b11148 transformers available for purchase some time soon. but there are some other projects in the pipe first.
ed
edit: mixup in the turns numbers
edit again: mixup in the wire gage