If you are on Facebook,you might try this 2 groups,there is a lot of information of online classes and procedures. Ask questions.........
SilverSmithing and Jewellery
Inspiring Metalsmiths Jewelry
You might find this interesting...
Revere Academy closed 4 years ago.Alan does spent a little time in a couple jewellery making Facebook groups and one group which does the projects from his Professional Jewelry Making book.There are also videos of the projects at this YouTube link...
The main question is why you would use casting grain instead of just ordering wire? I was taught never to use casting grain for anything other than casting. No metal from any company is perfect at all times. Many years ago I worked 2 pieces of 18K red at today's price would be around...
A standard 4 inch throat saw frame would have no problems with piercing that size metal sheet. In the photos the open work panels do look like they were cast.
It depends on what designs you want to engrave. A few simple accent lines or a complicated design? 2 or 3 engraver shapes will do almost everything,maybe post a design you would like to try. Example with flat and square graver used.
I think it was a context problem or maybe Google translation,East versus West usage. A couple weeks ago on another forum an Italian woman showed her jewelry and called it "tunneling" work,it was pierced work with a jeweler's saw.
If you were a enrolled student they have a 96% off option. https://www.corel.com/en/students/how-to-buy/eligibility/
I believe there is a trial short term option also on the website.
Take a look at options and the amount of money you can afford.... https://www.bladesmithsforum.com/index.php?/topic/24166-simple-engraving-for-knifemakers/
James Binnion's blog toward the bottom of the page,it does happen but it is environmental and body chemistry. You can look at his examples,but the piece I have worn for the last 30 years shows little corrosion. https://mokume-gane.com/blog/