Pulse 1 on this welder is to burn away oil and dirt and pulse two makes the actual weld. I have many guys telling me that they set pulse one much higher to get two welds in one. Unfortunately, that's not how it works. Pulse one will join the two metals lowering the resistance and the energy of pulse two will take the shortest path to the other electrode doing basically nothing. In other words, If a 3ms pulse is enough to adhere the metals being welded and you set pulse one to 3ms and pulse two to 12ms then you will get one weak weld formed by the 3ms pulse and not the 12ms pulse.
To make decent welds with a dual pulse welder you should turn pulse one off and find a voltage and pulse 2 setting that gives you good solid welds. Leave the welder on the determined voltage and set both pulse potentiometers to 0, adjust pulse one to a low setting and make a weld. Keep on adjusting pulse one higher until the metals starts to adhere, decrease pulse one potentiometer about 3%. Set pulse two to the determined setting above and you should get really good welds.
The size of your electrodes and cable to your electrodes makes a big difference. A 4 feet long #0 welding cable will give you twice the current than a 4 Feet #8 welding cable. Do not make your cables shorter than 4 feet though.