I saw a comment in a post the other day saying that Harvest wasn't profitable and that using the Horned Scarab of Awakening wasn't worth the investment. So is that true?

I focused on yellow juice (obviously) and red juice (seemed to sell quicker than blue). I also chose all Quantity/Rarity Eater altars as my build can handle pretty much everything (Still had the occasional death but who cares). I recorded the map quantity upon entering the Sacred Grove.

I have also been running this and I felt like with only yellow's chance reduced, too many of my maps had ZERO yellow. And this completely ruins the map. So I have yellow maximally reduced, but also reduce blue+red a little bit, this cancels out a little bit of yellows reduction so that instead of 0-2 yellows I am hoping for 1-3 yellows.

From my experience as well, having 3 yellow is still perfectly fine. But having zero is just the worst, you get a bit of blue juice and maybe not even break even since the scarabs are a divine each in Path of Exile.

So I've run probably 500 or 600 harvest maps at this point if not more and I've found it really depends if you're running Awakening or not. Without it, you want that reduced yellow because that way you're more likely to get that one juiced yellow, which is about what you can expect.

With awakening and the big price difference between the three types (yellow being like, twice as valuable as the rest), you can have three blue/purple and five yellow and still make profit off of just the yellow. Or five blue/purple leads to three really super juiced yellows. Etc. But if you have enough PoE Items, it will be much easier.

So without awakening I would reduce Yellow, with Awakening I would reduce purple or blue but not both.

I take the other 2 nodes cause it gives the opportunity to have a few more yellow plots. I didn't track specific numbers based on number of plots but in general it did feel like when I had 2 or 3 yellow plots with 5-8 T3 monsters gave more juice than one super juiced yellow. I didn't track the data to support this but I have also seen a variety of atlas trees like you mentioned. Now it may be more profitable running only the reduced yellow but I feel like you'd end up with more dry spouts of no yellow plots more often than not which makes it feel like you're wasting the Horned scarab.