StephanusThie wrote:With single flowmeter wouldn't the flow be divided by 2?
Indeed. However, most people use more gas than they need, so no effect. If there is a problem, just turn the flow rate up to compensate.
A flowmeter is two devices in one. There is a regulator to bring bottle pressure down to a manageable (usually fixed) level. Mine is set at 60 psi. Then, the flowmeter restricts the total flow, usually through a needle valve. The flow available is a function of regulator pressure versus downstream restrictions.
An alternative setup, which I use when welding outside and may require a large flow to counteract wind, is an oxygen regulator, with no flowmeter attached. I control the flow with the torch-mounted valve. With this setup, you can run three or four torches (or more on a windless day) from a single regulator.
With a two-piece flowmeter (the glass-and-ball type), you can put several of the flowmeter parts on a manifold fed by a single O2 regulator and operate many machines and/or purges at once. Think about how much oxygen comes through a torch regulator to feed a #2 cutting tip.
To answer the original post again, if you're not using both machines at once, no worries. A Wye or Tee fitting will do the job just fine, and none of this applies to your case. If you ever do need to run both at once, just be aware that if you have any trouble, the solution is to turn up the flow about 50% to double.
Steve