I have a TA-15 on order from Sweetwater, which I would like to use with one or both 8 ohm 1-12" cabs (one open back EVM, and one Thiele) that I currently use with my Mark IV. The on-line manual pictures a range of generic speaker connection options, but not the connection of two 8 ohm cabs to each of the TA-15's available speaker outputs. Is there any concern with individually connecting two 8 ohm cabs simultaneously, one to the 8 ohm speaker output and one to the 4 ohm speaker output? Is that a safe mismatch?