Obviously we can figure out a correction factor to use, but I would like to keep the design premise of having a direct lumens reading with no math involved.
Before any modding, the important thing is for the owners to not permanently alter the calibration that TA put on the tubes. So I was trying to figure out a way to reduce all output by a certain percentage.
Maybe making the centering discs do double duty is an option. Keep the reflective tape on one side, but change the silver paint to a less reflective color on the other side.
Instead of repainting, maybe cover the painted side in an adhesive backed felt in a specific color such as black or brown. Felt might be more consistent than paint. The problem with altering the entrance of the tube is that different beam shapes may be affected to differing degrees.
If we need a 50 or 60 percent reduction in output across the board, then we might need to look at the sensor end of the tube. Maybe a thin sheet of tissue paper over the sensor and then stick it in the hole would get the job done. This way you could still have TA’s calibration and then have your own calibration which might be closer to accurate.
So a theory - TA buys a stack of tissue paper, like waxed for instance, tests it out, gets a proper reduction across the board for all light types, then mails out a few sheets to all owners. Maybe we send a few bucks to cover envelopes, stamps and the extra effort. Then everyone’s lights would still be calibrated to each other. Plus we could simply remove the single sheet of tissue paper over the sensor and be right back to stock.
Just a thought.