Yes, definitely keep the input levels at 12 o' clock and nothing higher. Also, if using a DSR1 you may need to bring the input levels down even further since that unit increases the pre-out voltage. As always be aware of what frequencies in the EQ you are adjusting, typically you want to cut EQ bands and keep minimal boost if possible.

 

it's odd that the Mmats can handle the power but the TMS69 speakers have to be dialed back.