You’ll get more responses by just asking the question. If you say, “I have questions” by don’t say what they are, no one will know if they can answer, and are less likely to volunteer.
You can speed up the job a lot by going to Edit > Device Settings and enabling ‘Fast Whitespace Skip’ and give it a speed like 4500 mm/min or whatever your machine is capable of without skipping. That file, since there is no shading, would work a little better as ‘Threshold’ instead of Jarvis.
If you want it darker, you will likely have to slow down a bit, though that might make the weird burned corner turn up more. That is likely something inside the material, like filler, getting burned and causing soot.
