I saw the fish we received and I think we got 12 of each... This may change though as the owner will probably want more fish than that lol.
Yeah, they'll be lost in a tank that size - you could bump the shoals up to 50 of each, and still not see that many at once.
I went ahead and doubled the gluconate to 0.8 ppm weekly and doubled DTPA to 0.4 weekly. I've been thinking of other solutions however.
That sounds like a lot to me along with the EDTA in the micro mix, and could exacerbate the algae growth and I'm not sure throwing more of the same stuff at the tank will necessarily be the solution. Could you not try the EDDHSA chelated iron that @xZaiox suggested earlier in the thread?
The idea is basically to add the daily dose of micros/iron powder to the container ewithout mixing it and slowly pass water through it to very slowly dissolve it and add it to the tank.
That sounds like a recipe for massive dosing inconsistency. Is there are particular reason you/your client don't want to stump up for an auto-doser - you should be able pick up a basic 2-channel one for $50 on your side of the pond (maybe less if you shop around).