Hello guys!
I've transplanted into 2liters as of a couple days ago and just yesterday popped them over to 12/12 (see attached).
It appears that my yellowing/spotting is contained to the few lower leaves that it was originally on and is NOT spreading further upward at this time. I plan on lollipopping these in a couple weeks anyway so what little damage there is will be a non-issue soon anyway.
The plants are looking healthier at this point moreso than in any of my previous grows - it seems the increased Cal-Mag solved the issue! Thanks guys!
Lesson learned: Assuming you are using GH nutes lucas formula or equivalent, utilizing the hempy bucket system, and using 100% perlite as your medium, with RO water you WILL need a full dosage and change of Cal-Mag (5-8ml per gal) every feeding.