FWIW, running the 3A converters at 1.5 amps things get pretty warm, so I'd set the estimate at 50-75 20ma LED's as a practical limitation. The regulator IC they use is rated at 3 amps, but that assumes a pretty good heatsink. Also, to draw more power from these would likely require heatsinking the bridge rectifier and increasing the filter capacitor value.
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