What setting do I use to engrave on acacia wood?
The only thing to do is experiment. I made a bunch of half inch squares and typed in the settings I was going to use and engraved those into the the square, and then experimented with different settings to cut the squares out. Start low and get hotter which means start fast and get slower. You will find the official numbers for walnut to be a good starting point.
Welcome to the forum.
When using non Proofgrade materials, it is necessary to do some testing to get the results you desire. Over the years, there have been discussions of acacia, and here are some threads for your review: Search results for 'acacia' - Glowforge Owners Forum
That all depends on what effect you are after. Test all the things, it’s a treasure hunt.