Hi ycwbycwb
The only Metco parameters I have for 73F-NS-1 or 2 with Ar/H2 were standard may be 10 or more years ago for 7/9MB, so they may have been revised.
GE/731A Nozzle
#2 powder port
Ar 160 FMR @ 100 psi (6.9 bar)
H2 80% (low capacity flow tube) @ 50psi (3.4 bar)
400A @ 50 - 55V
50 FMR carrier gas flow
11lb/hr (5 kg/hr) powder feed rate
3" (75 mm) spray distance
Ar 160 FMR @100 psi should roughly be 180 SCFH
H2 flow I have no conversion info, but going by voltage your flows appear higher (assuming you are using same nozzle and hardware).
These parameters should give coatings ~3% porosity and cross-sectional hardness 750 - 950 HV/0.3. If you need better coatings, you will need to use Ar only or Ar/He parameters.
You can certainly see the difference in coating structure corresponding to higher primary flow (higher velocity, lower dwell time) in coating 2.
Hope that helps