some time ago, john henley sent such a calculator to this forum. try the search feature to see if it is there. i have it in my system, but do not know how to copy the link to it.
drawing is the boss of all you want to learn. personallly, i like to draw oversize, refine where needed, then scan to size. or, in some cases, it's very difficult and time wasting to try transfers onto compound curves. solution direct draw on the part. the software that assists in drawing can...
it's a shame there aren't more people like you in this world. youngsters these days are in great need of guidance in whatever form. i finally got my one grandson to learn welding, use a plasma torch, and do blacksmithing. his favorite is pounding iron to make useful things. he loves my forge...
using a bit of lube-- mineral oil, kerosene, 3 in one wont hurt anything. who knows ? may help a bit. be sure to tape off any sensitive areas, if any, to keep things clean.
i wont advise which to buy, they are all good. be sure to start with the very basic scroll. no sense in practicing the more complicated layouts. no sense in going complex when the basics are a struggle. welcome to the forum,and good luck in yer adventure.
controlling the lighting would be a far cheaper alternative. translattion: probably a really good light ring and maybe fiddling with some sort of diffuser. the light ring should have dimming capability.
i've done several. lotsa fun doing them. as for money, i never really earned much that way. it all had to do with the quality of what i produced, therefor not really profitable considering time spent. to really earn big, you gotta really get good. too much competition out there.
i'm still using an ancient hp ink jet with #92 black. am also using an equally ancient hp laser unit that prints with magnetic ink. when either no longer is supported, i'm simply going to jump out my basement window ! technology is wonderful, but like time, it's always changing. sadly, no way...
with all the needed skills, there may be one missing. that would be running and operating a business. you must charge for all the time spent on drawing, tool sharpening, time talking to clients, engraving time, phone expense, heating, rent, and bla, bla, bla ! failure to charge all this...