Lower trip current still is a crapshoot with a short circuit line to PE, or even line to neutral, as the energy is enough in the single cycle to trigger both to disconnect. The only benefit is that the build up of stray currents in multiple device EMC filters will trip the lower one first.
Still, like the 2 rail system, and the nice socket sets as well. U see you have pretty much the same DIN mounting power meter I have, though I put the one i have into a small 4 wide DIN box with input and output cables, using a standard SA plug and a dual IEC socket ( old PC dual IEC power lead) for a connection. for things that do not have an IEC socket i have a flying lead with a SA standard socket outlet on it, with a 15A breaker as it was a recycled industrial socket outlet that came with a 15A breaker switch.