Ive mostly just been doing cutting on the big lasers but yesterday I tried to do some standard rastering on some black backer board and had mediocre results. If anyone has tips etc please let me know. I attached a picture below, as you can see the lines are not very crisp and leave residue. Compare to the same thing on the blue laser.
This is generally what I find to be true of rastering with Lightburn. I do a lot of rastering of vector graphics and have been sticking with Blue/Pearl for best results with those. I did do some rastering on Dorian with that material and had to scrub it with a toothbrush afterwards to get it to look decent.
Line Interval is very important, alongside power. Spot size is about 0.2mm on Tarkin but closer to 0.25mm on Dorian.
Do you want the clean light-colored background, or a darkened look? The lower one looks like it has way too big of an LI.
What was your line interval, power, and speed?
Do you remember what the settings were on Blue that gave you the look you wanted? We’re looking specifically at the Line Interval.
Line interval, make adjustments to taste.
As for smoke, ensure air assist is operating.
The Laguna has a control valve at the nozzle.
Open to full flow or, again, adjust to your taste. 
Rastering on Tarkin or Dorian for just a simple depth of block letter like this should only be MORE capable than Blue or Pearl.
But rastering is handled inside LB one of two way, whereas there’s only one mode on Blue/Pearl.
You can do uniform-depth Fill (or Fill+Line) of closed shapes, or actually Image raster a bitmap graphic (BMP, JPG, PNG, etc) which is a whole different thing with a lot of options. Fill offers control of the LI, speed, and power and there is no other variable. A monochrome bitmap graphic can be done as Image which is conceptually identical to Fill mode, but has many variables that change things.