We plan of building a few more OSH Park boards just to make sure the LED isn't wildly variable. We have a hidden mode in the firmware to blink out the ADC raw value so we can compare.
If readings are close, we'll send the design off to Seeed Studio and order a stainless steel stencil as well. We will probably not panelize since my reflow oven is small and I think I can be more steady manually placing parts if my hand can always rest fully on the work surface, vs hovering over a grid of solder-pasted boards. We'll build a jig to do them one at a time.