I recently picked up the Benomatic(Worthington) o2 cylinder and reg. At first I thought I would need to take it back because the o2 cylinder was so light, then saw it only holds 1.4 oz of O2. How long do do you need to oxygenate starters and buckets at low flow rates? And how long will these cylinders last? I have welding tanks but figured that the smaller worthington cylinder would be easier to handle.