The crude regulator (as you mentioned) is exactly why I stopped using it after the first bottle was gone. It seemed to go from zero to 100% with nothing between. I found some good regulators on ebay and even Amazon for pretty cheap money (Amazon has them for under $40 each). These connect to standard (welding connection) tanks too. No more using the 1.x oz tanks this way. Plus, with the regulator, with a flow meter, you KNOW what the flow rate is. I have one that shows me the rate and another that lets me set the rate.
I typically go for 1-2lpm for 1-2 minutes depending on the batch...
This O2 meter is on my short list of things to get. I will have it before I go to brew my next BIG brew (over 10%), which will be within the next few months. Then I'll also KNOW how much ppm of O2 I have in the wort before pitching the yeast. :rockin: