I'm wiring up a 2x12 with 2 8 ohm 25watt greenbacks. I have a solid state 50 watt Marshall head which requires a 4 ohm load minimum. I am NOT trying to maximize volume. What would be safer for my speakers - to wire them parallel at 4 ohms, or series at 16? I'm more concerned about the speakers than the head - it's a backup to my normal 15 watt head with will work fine either way. Any input would be greatly appreciated! Thanks!