@BigTlilOdd the problem winds up being a bunch of things. The engines on the A-10 are a pain to try to analog in RC. EDFs are the most efficient in terms of thrust to area, and look scale, but are horridly inefficient. The fore/aft inline power system through a duct is going to be even more inefficient than usual because there is a 0% chance of any additional air being sucked in by that second propeller. So you're stuck with maybe adding more blades to your prop for that added power, but that nacelle is right around 4", 5 if you really want to risk the props striking the inside of the foam nacelles in a hard landing, Meanwhile the C pack puts out more power than most of the offerings you will find in under a 5" propeller for multirotors, and will do it efficiently.
Another thing to consider is strength. There are a few notable weak spots, such as vertical stabs supported by bamboo skewers to maintain a vertical alignment, the interruption of the wing spars and panels at the bend, meaning the hot glue becomes a structural element, not just adhesive, the thickness of the elevator and rudders, etc. These are not a factor if you are using a propeller with high thrust at a low pitch speed, which will govern your speed well, but i will kind of gently point towards how beefy the build is on the Freewing A-10 if you consider a twin EDF build (multiple carbon rods running the fuselage, multiple carbon spars, screw-in construction, etc.) especially with larger fans.
This all being said, i have a pair of 90mm fans that just became available, and an a-10 kit in the garage, so the temptation is real...