Draw a picture, keep it simple. Everything is similar triangles. The offset of the hinge creates a triangle that has the same angles as the rise of the gate. The rise of the gate is an imaginary triangle underneath the gate panel.
The repeated arc burn will damage your skin. It is the same as sunburn in how it can increase your chances for cancer, it can also cause premature aging.
I had a pair of welding gloves that were a single thin layer of quite soft leather. The felt like driving gloves, and fit perfectly. I loved how they fit till they wore out. I haven't found a pair like them since, but I haven't looked very hard. My mistake was wearing them as a general work glove!
"Sunburn" from a welder arc flash is WAY worse than sunburn. Get some gloves and wear sleeves, same with your assistants. You may also want to cover your neck. Yes, PPE can be hot and uncomfortable, but there are selections that can be made to help with your climate.
How's your back feel? That pose is not good for lifting, or staying still for very long, but if your back can take it then OK then...at least for now. Sawhorses are worth their weight in gold sometimes. They make the back feel better at the end of the day.
It is a simple gate that looks good. Is the client happy?
If you have a means to SAW the rail (that is a power hacksaw, abrasive cutoff saw, or stock cutting bandsaw, not a hand saw, although determination will get you there...eventually) saw a few pieces about 1 inch thick, or the size of your hardy. You can then cut these down and/or reforge to make tooling.
I find coil spring moves easily at the right temperature. When it gets stiff it is too cold, and still glowing. It requires a few normalization cycles to refine the grain prior to hardening.
Too hot and it kicks off more than a spark or two, or crumbles. Start with more material than you need and DON'T BE AFRAID TO RUIN IT!!! Run it hotter and hotter until it misbehaves, then cut off the bad piece and try to get not quite that hot.
Diagonal fitting hot-cuts with a tapered shank made from leaf spring are rather nice. the tool can be pretty ugly and work great still. With a curved top they can cant in the hardy before jamming and still be easy to use. They also fit different anvils since they just seat differently.
Remember that fines can be wet and used, so "too small" is just a handling inconvenience. The fire doesn't care so sweep them up!
If your forge table is big enough you can coke up to baseball pieces and break the soft breeze coke off as needed...Of course this doesn't work if ALL the coal is that size, but for a few pieces it is easy.
If you don't have torch tip files (tiny wire files, usually in a set) get a set before opening this up. You may have trash or damage to the tip of the orifice. A little tip file can clean any trash inside the orifice out and make life nice.
I had an interesting curl of flame inside the burner when I built my forge burners. A sharp edge is needed so the fuel gasses part from the nozzle and continue in the desired direction.