Running 4 ohm taps generally tightens bass performance, but can lead to a drier sound. Only by listening to both connections will you be able to determine which is preferable to you.
Also, the 8 ohm speakers likely have impedance dips well below 8 ohms, perhaps even below 4 ohms. So, using 4 ohm taps might actually be more appropriate than using 8 ohm taps.
Also, the 8 ohm speakers likely have impedance dips well below 8 ohms, perhaps even below 4 ohms. So, using 4 ohm taps might actually be more appropriate than using 8 ohm taps.

