Use Smiths Ar/H Mixer on Ar/CO2

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I ran into a deal on the uber stainless Smiths Ar/H High Capacity gas mixer 299-016-16B.The two dials range from 50 to 100 and both controls are supposed to be set on the same number.Well 100,100 is obviously 100% Ar and 50,50 is 50%Ar, 50%H.I was thinking I might be able to use this to blend Ar CO2 on my MIG.Two Potential Problems:At a 50,50 setting, due to the small orifice needed for Hydrogen, I'm thinking I may not be able to flow 25% CO2 through that orifice.Will the unit operate properly at a Flow Rate less than the 20-700 SCFH spec?I emailed Smiths and they did not reply I'm guessing due to liability issues.Any thoughts?TomPS.  On the other hand, might I have any use for Ar/H ???  I'm going to be trying Silicon Bronze MIG for auto body, but other than that, everything else should be same old.
Reply:I had the same questions when I saw that same mixer on ebay last month.  The bids went out of my range by the end but were still very economical compared to new.  Gone are the days when some of the guys here got one for $75 or $100.
Reply:Call Smith, they are very helpful.I have an Argon O2 mixer.  Now we are talking heavier gases.  The only difference in part numbers between mine and an argon/CO2 mixer was the front dial....Yep, the calibration was in the front dial.I used an OTC automotive 5 gas analyzer to calibrate it.  Unsing C25 and pure argon, I could clearly see where I hit 20% CO2 (the best the analyzer can do) and it was pretty linear all the way down to pure argon.  Argon showed up as O2.  So according to my 5 gas, I could mix from 80% to 0%.Now the bad news.  From about 15% CO2 to 25% there isn't a whole lot of difference for short circuit welding on steel.  With pulse, the ability to dial 10% helps, but quite frankly I like short arc better (I like seeing the wire hit the puddle).  I'm holding on to my setup (Including regulators and flow meters, and custom hoses, I have over $500 invested + some used flow meters.)  The only thing it buys me is that smaller quantities of 90/10 are expensive and custom (1-2 week lead time).Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:New to welding, but have been burning for some time and have a lot of experience with many different gas product manufacturers.  Smith stuff doesnt last!  The best out there is Concoa, Harris, and Rego for guages, mixing stations, torches, etc.