I have been mounting my Vero's with just screws. 3590 with ideal holders. This has been test platform for a while. Active cooled 120mm fan
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I usually put Vero clamp (reflector Holder) only when checking Tc. I have not been using clamp on Vero for PAR charts after i saw your results that the clamp actually works like optic.
I think the ideal holder for 3590 should not change the light distribution as it is flat. However the reflector adapter on Ideal holder should change numbers just like Vero Clamp.
For veg lamps i am going to use Vero clamp without the reflectors just to focus the light slightly. Thanks for your research.
Those luna 200 cost just a little less than CXB 3070. However the performance does not look as impressive. It is like under driving a large inferior cob. It may have better thermal dissipation for over driving but the efficiency is not impressive. Luna 200 is rated for 422.3, vero 29 is rated for 4.2 amps aprox 170 watts. Vero is cheaper and still beats Luna in efficiency