For cans 45 ohms to about 200 ohms, the best available option based on the turns ratios would be the highest impedance (0.25 watt, which is blue on my sample, and 600 ohms DC resistance to black=ground) to the preamp, and the lowest impedance (10 watt, which is brown on my my sample and 42 ohms to black=ground) to the headphone. Check the DC resistances to be sure you have the correct taps.

For cans below 45 ohms, use the 8 ohm secondary, and try different primaries - 0.25W, 0.5W, and 1W.

In both cases, listen for a lack of treble and/or bass. It might be worth changing these taps if one problem predominates over the other. You may find you have to choose between higher signal and better spectral balance, if your cans are not very sensitive.

I have not done a detailed study of this transformer, just measured the turns ratios so far. They seem to be as advertised (my earlier measurement of the 8-ohm tap was in error, or at least I got a different number tonight - and the new number agrees with the labeling.)