0You are asking about the hardness of vacuum. The lower the pressure, the harder the vacuum.
Outer space has a vacuum average around 10−11">10−1110−11Pa, but it will vary depending on where you are … for comparison, the LHC maintains a vacuum around 10−7">10−710−7Pa.
However - a vacuum contains “vacuum fluctuations” - as virtual particles pop in and out of existence at random. It is where you get vacuum energy from. You can reduce the possible ways that this can happen by putting large flat conductors very close together. It is called the Casimir effect.
In principle, therefore, the space between the plates has a harder vacuum than the space the dishes are in. So set up a Casimir experiment in deep space to get a harder vacuum. The relative hardness will depend on engineering limits.
For all practical purposes though, you don’t get a harder vacuum than some small volume of deep space between galactic clusters.
