Dual Rectifier 3ch dummy question

[Raggi73]

Hi. I'm new to the board so..... Anyway. I have a Mesa traditional 4x12 cabinet (8 ohm) and a Randall 4x12 (8 ohm). I'm using both in the rehearsal space but do I connect them to the 8 Ohm output or the 4 ohm?
Sorry for the stupid question.

From what I have read I should use the two 4 ohm outputs? Just want to make sure.

 

[Emi]

You need to use the two 4 Ohm outputs to use two 8 ohm speakers.