Lumens do not add up like that - just as a note. You can't go 65Klumens per square meter x 6 square meters = so many lumens output - that's not true and that is not how lumens are measured to begin with.
And I've done the research on the sulphur plasma lights - they are inefficient and they do not compare.
http://www.sulfur-plasma.ch/Technical.html
Not very good spectral output, and highly inefficient if you're using the plain sulphur plasma. Now, a Sulphur/calcium bromide lamp would do better, as the chart indicates. However, this still would not compare to primary color T5HO lighting. Plus, the power conversion loss because of multiple steps (HID lamps go main>ballast>arc tube whereas your sulphur plasma light goes main>ballast>magnetotron>bulb and the extra step in energy conversion creates more heat output and inefficiencies.
The Plasma Halide lamps I just mentioned, in theory, at 700w would do double what your current sulphur plasma lamp does. They only have 250w versions until they can enhance bulb strength for higher wattages.