Does the PAVE-Seal versions with insulated and stranded conductors have a much higher leak rate compared to the PAVE-Mate styles with solid pins?
No. There is no difference whether the conductors are insulated wires or cables or pins. All wiring is specially sealed and processed to prevent any significant or detectable leakage through the wire or cables, including any shielding. This applies whether the requirements involve gas, fluids (oils, solvents, fuels, saltwater, freons, etc), vacuum, low or no pressure water vapor or high pressures of 30 to +1000 bar.