Bi wiring a tube amp is very effective when you have 0 - 4 - 8 - 16 ohm connections. Use the "4" as "common" and the "0" for woofer, and the "16" for the tweeter. Polarity of the tweeter may have to be reversed. Easy enough.
Now the thinner (usually) 16 ohm wire inside the transformer only carries the tweeter current. Thinner wire has better skin effect properties for higher frequencies too.
The voltage on 0-4 and 4-16 pairs are the same but phase is opposite with 4 as neutral. 8 has lower voltage, which can be OK is the tweeter is "hot" and you want to lower it.
Try it. Nothing bad will happen.
Now the thinner (usually) 16 ohm wire inside the transformer only carries the tweeter current. Thinner wire has better skin effect properties for higher frequencies too.
The voltage on 0-4 and 4-16 pairs are the same but phase is opposite with 4 as neutral. 8 has lower voltage, which can be OK is the tweeter is "hot" and you want to lower it.
Try it. Nothing bad will happen.