All the sample sizes you sent were welded at 1100ws total energy. Pulse 1 was set to 50ws energy to help burn off any contaminants, and pulse 2 was set to 1050ws energy to perform the weld.
We did not weld the galvanized samples (the zinc in the galvanic coating does not allow for good welds). The thickness of the steel requires large amounts of energy to achieve strong welds.
The CD1100DPM2 is able to tack the steel in place, but permanent welds would require a stronger unit or an AC welder. It is extremely helpful to have the mating surfaces as flat as possible to get the best results.
The CD1100DPM2 and PASP-HP hand piece can perform semi-permanent tack welds on the steel samples you provided. The thinner gauges will have stronger welds.