The capacitance of the Earth is estimated to be in the vicinity of 711 micro Farads on the presumption that it is a solid sphere whose outer concentric shell is infinitely distant. But, what if it is hollow with a presumed thickness of 1 kilometer or less?

6,367.5 km = radius of the Earth
https://en.wikipedia.org/wiki/Earth_radius

1,000 km = assumed thickness of the Earth's shell -- probably less than this

"The refractive index of a nonmagnetic material is the square root of its relative permittivity."
https://glossary.ametsoc.org/wiki/Relative_permittivity

Since the dielectric constant, or: relative permittivity, of a material is the square of its refractive index, and the refractive index of granite bedrock is somewhere between 2 and 3.5, then the average refractive index of granite is 2.75 and its square is 7.5625.
http://eodg.atm.ox.ac.uk/ARIA/data?Rocks_and_Conglomerates/Granite_(Toon_et_al._1977)/granite_Toon_1977.ri
for comparison
http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/diel.html

outer surface diameter versus inner surface diameter of Earth's shell
6,367.5 km - 1,000 km = 5,367.5 km

capacitance of two concentric spheres in which the larger sphere is r1 (the outer surface of Earth)

(4 x Pi x dielectric constant of the material x r1 x r2) / (r1 - r2) = capacitance
https://www.toppr.com/ask/en-us/question/the-capacitance-of-two-concentric-spherical-shells-of-radii-r1/

6,367.5 km x 5,367.5 km    34,177,556.25 km
------------------------ = ---------------- = 34,177.55625 km x 12.566370614359172953850573533118 x 7.5625 ~= 3.25 Mega Farads!... or more...!!!
6,367.5 km - 5,367.5 km         1,000 km

Conclusion
Since my simulation requires the presumption of the maximum capacitance of the Earth is no greater than 99nF, this circuit may not give the expected results unless some modification can be devised which overrides the Earth's capacitance?

Maybe a 10pF capacitor should be built into each of the nine or more grounding rods above where each rod enters into the Earth?

And, ... since this circuit tends to develop high nodal voltages ...

For safety's sake, maybe a dielectric goo should be poured into this circuit's project box to solidify into an immersion of a dielectric medium after, first, lining the interior surface of the project box with conductive plates and each plate is separately (?) connected to its own Earth ground?