5. Not sure why does the wall mounted line has to sit low or high.
Looks like you have most things above covered.
One aspect to look into if this is all set up inside your home is the insurance aspects in the event of a fire.
Although I can't comment on American or Canadian insurance providers in the UK we have a requirement of an Insurance assessor in the event of a large claim. They are sent in on the bigger claims to inspect and in effect negate the claim or at the very least reduce the pay out.
The use of a workshop is fine until you get to the level of mechanical and electrical equipment.
This increases the risk of a negated claim and in cases of folk having a welder or soldering process going up to the risks of a siversmith process refining silver for your jewellery hobby you get the picture.
With diving and paint ball etc the use of an air compressor seems to be OK but its when you get into nitrox and trimix that the problem starts and the risks begin to manifold.
Filling scuba cylinders with air using an air compressor is a simple accepted insurance risk under a household policy but mixing or blending gas especially with oxygen is now being classes within the confines of an industrial process and a couple of folk have found themselves without any pay out.
The act of mixing or blending a gas with oxygen is by definition an industrial process.
This it would appear includes partial pressure filling as well as continuous blending despite the variance of risk.
It is further compounded by using an air compressor hence why I keep banging on about read the manufacturers
metal label on the compressor it says Air Compressor not nitrox not heliox not oxygen or trimix and you're screwed. Note the fancy green and yellow sticker doesn't cut it with them either.
Further the meal label attached to the block if It has no stated upper oxygen or gas mix limit and so again the insurer reverts back to the recognised standard being that any gas with a percentage of oxygen greater than 23 percent shall be classed as oxygen. And you're screwed again with a rejected household insurance policy with the house gone and living with the in-laws or the street.
(Other interesting examples was a scuba diver in a multi story rented flat and a small scuba compressor, The recharging of electrical scooters using Chinese batteries out of Amazon and eBay and so on )
But in answer to the question why fix the high pressure horizontal lines height. High and Low
This is to avoid in the event of a burst the tube whipping back and taking your face off therefore we tend to mount higher and in the event of mounting the lines lower engineers tend to mount them lower than the junk needed by which to do your part in creating the next of kin. The same level of care goes in mounting cheap Chinese pressure gauges at eye level that are for hydraulic fluids and not Safety Pattern for gases.
