His main point I think, was that his Cura profile for pla made the most difference. He is most likely right about this as the video evidence shows and you can't fault him for this. He goes on to talk about Chris Riley and his own follow up video about Chucks results, and posits other takes on what is going on.
Chris uses tape to block the flow and this was one of the options I suggested in Part 1. I didn't even consider tape for it in this location though, I was thinking to place it over the bottom third of the face of the fan for testing lol.
My mind was stuck on designing and making a solid set of partitions for everything. D'oh!
(Slowly licks closest window, while drooling heavily lol)
My own issue and focus still, is that if you're only printing pla then you probably wont need to take this research any further. My continuing issue with it, is that profiles etc, dont always translate over to other filaments like petg that are often fussed over in trying to get them correct and string free, and I suspect this applies to other types of filament as well.
Not being able to control what and where things are being cooled limits you and reduces the control you have over the process.
You only need to look back to how the Prusa extruder is set up and how it works with target specific fans doing different jobs individually. This gives you more control, and I prefer this thought process.
I haven't looked at the Hero Me Fan Duct closely yet, but will find it and link to it in here so everything is together.
Here is the general search on Thingiverse on the "Hero Me by mediaman" as there are a number of revisions and versions with extras etc
Here is the OEM or original Creality extruder setup with a leveling probe allowance.
Here are the two I'm thinking of as they match whats going on in my addled brain atm
I think the only thing to do at this point is to print the Hero Me files and test it out on my rig, and test some petg with stringing tests, to see how well it works.
I also have some spare e3d v6 direct drive setups and a Titan extruder that I could take off one of the other printers. One is already half disassembled right now anyway, and make a design for them, but lets not have another unfinished project laying around right now lol