DIY advice - Bridgelux or Samsung
 

I'm moving to a new place in a bit, and the light is lower so time to engage in some DIY cost-saving magic. General plan is to mount these on a few ~2 ft wide baker racks that will be adjacent to north-facing windows to supplement current lighting plan. Not only orchids will be here, but some succulents, bougainvilleas, etc. Anyway, does anybody here have some input between these options? Leaning towards the options listed below, or derivations thereof, rather than cheap Home Depot shop lights as the spatial extent and light intensity needed makes the efficiency non-negligable from my back-of-the-envelope estimates.

First question - Samsung Q series vs the Bridgelux EB gen 2.

The Samsung Q is so efficient (203 lumens / watt), I can't see using the H series, since I cant find it for substantially cheaper. But will I really notice an extra ~20 lumens per watt between 187 and 203? I feel like wiring, temperature, driver inefficiencies etc. will mask this, so the Bridgelux wouldn't be too substantially different. What am I missing?

Second question that ties into the first, how much should I shoot for 4000K over 5000K? Not really a matter for the Samsung Q (same price on digikey) but the 5000K Bridgelux is currently at like 6 bucks and free shipping on arrow currently, so that seems like a major steal, vs the ~10-11 for the 4000K. Also, does anyone who knows Bridgelux more specifically know why this price differential occurs? They both seem to be Gen2, but am I missing anything?

Currently I'm leaning towards just getting the 5000K Bridgelux, mostly based balancing up-front cost and estimated efficiency. This sound like a good choice to you?

Actually, Samsung F-series is probably better deal than Q (I haven't checked it recently, but I think it is still true). Note that these efficacy is at the nominal current. So if you drive them with lower current, they can have higher efficacy. F uses same diodes as H, but it has 1.5x more diodes. For F, I would use much lower current to achieve high efficacy. When I compared, Samsung F (driven softly) and Bridgelux EB is pretty much similar in cost and performance. So either one will work well for you.

I prefer lower temp, but with that much price difference, I would go with 5000K. The difference between 4000K and 5000K for plants are pretty small. With tat price (assuming that it is Gen 2), EB 5000K sounds like the winner. I don't know why there is price difference, but I also found a bargain for 5000K cree CXB3590 cob a couple years ago (much cheaper than other color temp), and I went with them.

With these, you probably don't need a heatsink (if you go under the nominal current).

Thanks naoki! As always, you are a wealth of information.