[morzh]

Ok.

Don't confuse the tubes' expected load impedance and DC resistance of your primary.
I do not have the sch in front of me, so I will be pulling the numbers out of you know what, but here it goes:

Say, your expected pushpull load impedance is 10 kOhm (see tubes' datasheet).
Your voice coil, let's say, about 1.1 Ohm.
This means, you need 95 turns ratio (9,000 impedances ratio) to convert 1.1 to 10,000.

Your transformer will show the coil resistance on top and your load impedance in teh coil under it. Your ratio is 9,000.
9,000 times 1.1 is 10000. But you have 1.5, so look for the value app 1.5 x 9000 which would be 13,500. The closest is 16500. This will be achieved connecting your voice coil to Wires 3&4.

Now, if you know exact voice coil impedance, use that instead of 1.1 ohm.