6.5 for color here. machine bogs a bit with 11mag but puts in color most efficiently for me. i do need to slow my hand speed a little but the ink saturates faster. i find i have to work the skin more any higher than 6.5. this is using 3.2mm stroke. almost no give. i do mostly japanese style. kinda like coil machine theory. slow and punchy. but thats just me.