Kenneth Grimm, K4XL wrote:
"Will the eight 5 ft rods give me the same "ground" as the four 10 ft
rods?"

Maybe better.

Skin effect depends upon conductivity. On copper it is measured in
thousandths of an inch but in the earth`s surface, penetration may be 10
or 20 feet.

Skin thickness is also inversely proportional to the square root of the
frequency but does not change much sbove about 6 MHz due to electrical
capacitance in the soil which makes it appear more of a lossy
capacitance (dielectric) than a poor conductor.

Soil with a conductance of 6 mmho/meter has a dielectric thickness of
about 8 feet at 6 MHz. A ground rod which would reach the depth of
energy penetration is recommended. E.A. Laport says at the end of page
49 of "Radio Antenna Engineering": "Ideally, the ground rods should
reach down to the depth corresponding to the skin thickness for the soil
conductivity and the operating frequency."

However, using eight 5 ft rods instead of four 10 ft rods would likely
improve a grounding system especially if the rods are placed some
distance away from their common connection point, say 10 feet or more.
The interconnection wiring acts somewhat as a radial system and will
have substantial capacitive coupling to the earth at freuencies where
the earth`s dielectric properties prevail.

Best regards, Richard Harrison, KB5WZI