Hateto burst your bubble, but HPS bulbs are almost all Yellow, useless light.
With very little red, and a little blue.
The only spike in the red is yellow.
With all due respect, this is the kind of statement that makes PAR growers look bad. Yellow is not useless light, green is not useless light. Red wavelengths are severely over-rated by ganj growers because they mistakenly think the PAR graph applies to plants exclusively. (it is a combined pigment absorbance graph, meaning that there are pigments on the graph which plants do not possess) HPS's do obviously emit plant usable light, and plenty of it (intensity) no the spectrum is not "good quality light" but to claim that yellow light is unusable to plants is to jeopardize the integrity of your other pretty spot on statements.
Yellow/Green light are obviously highly reflected by leaves (infrared in excess of 740nm as well) this means that they are the most reflected light types in the canopy while still showing 23%+ use in photosynthetic processes. This means that the other 77% that is not diffused or scattered or absorbed by some other pigment, just rockets from one chloroplast to another, deep into the canopy and even along and inside a leaf itself, according to "Green Light Drives CO2 Fixation Deep within Leaves"
(Jindong Sun, John N. Nishio2 and Thomas C. Vogelmann). Ganj growers often refer to this effect as "penetration" if a light possesses enough yellow/green/IR to bounce through all/most parts of the canopy.
Where you fall short with HPSs is with the phenotypic expression of terpenes, a number of cannabinoids, and the severe climate factors you introduce. I think it should be noted, however, that plant's (higher plants at least) seem to experience a higher oversaturation point with yellow/green light meaning you can force-feed them more of this light than other types. So while you are supplementing your hortilux with RED LEDs, blueb, be careful not to overdo the red. Maybe make 2-3 units to spread, since you are opting for such high watt diodes. (yea you can run them at lower wattage but why would you?) Plenty of stories on the net of people bleaching leaves with overly intense red units.
Hope i balanced criticism with helpful info.
C.indica--
Not trying to throw you a dig, I'd expect the same if someone found me trippin up,
MPP
edit:
Lack of penetration is why us t5er's Scrog/Sog/LST/crop/top etc, unless we roll like phaeton(sp?) and just surround the bitches