A simple test to figure out what the pixel hit resolution parameter does:

Use Technical proposal benchmark as reference:

Default pixel resolution is written down in this file:
tkgeometry/config/stdinclude/ModuleTypes/pixel

resolutionLocalX 0.013
resolutionLocalY 0.028

pt 	1000
Real 	2.30948
Ideal 	0.53651
Loss 	4.3 

d 	1000
Real 	0.00601
Ideal 	0.00241
Loss 	2.5 

z0 	1000
Real 	0.00696
Ideal 	0.00273
Loss 	2.5 

Make the following change to Barrel BPX in PixelTechnicalProposal2014.cfg:
    Layer 1,2,3,4 {
      resolutionLocalX 0.001 // 1 um
    }

pt 	1000
Real 	2.18685
Ideal 	0.04127
Loss 	53.0 

Make the following change to Barrel BPX in PixelTechnicalProposal2014.cfg:
    Layer 1,2,3,4 {
      resolutionLocalY 0.001 // 1 um
    }

pt 	1000
Real 	2.30948
Ideal 	0.53651
Loss 	4.3 

z0 	1000
Real 	0.00496
Ideal 	0.00010
Loss 	50.8