Floorguy,
You brought up the numero uno reason to keep mechanical devices with small parts away from the inlet side of the blower.
While placement "may" arguably protect the blower infinitesimally better in cases of poor vac filter maintenance, it represents a greater hazard due to potential mechanical failure. I think it is a really good idea to have the vac filter between the relief valve and the blower inlet, which is what placement on the vacuum tank exactly does.
Those are awesome pics. I'll have to refer back to them when again I have a discussion with one preaching for a vac relief valve above/before the blower.