You can edit the 3.8W tool and rename it “7W”. In the power section, put “7W”.
In the “kerf” setting we use 0.006" for most wood types. If you see overlap in the burn, then you can use a bit larger like “0.007”. If you notice white space between the lines, then make it slightly smaller. For different materials that don’t have as much char, like dark acrylic, then we use a lower number like 0.005". I would put it as 0.006" and try it out.
For move speed, we normally start at 80 inch/min for most wood. The slower you go (lower the number) then the darker it will get. The higher the number, the lighter it will be. You need to try on scrap pieces to get the level that you thing is good for your project. Different wood will give different levels of darkness for the same speed.
“Maximum burn rate” is just for the preview window in the toolpath section. You can change this number is the preview doesn’t look good. I personally don’t use the preview in the toolpath area so I am not sure exactly what this number needs to be. I usually leave it the same as the move speed.
Make sure your units are in inch/min (or mm/min). I would keep them similar to what you use on the CNC side.
We normally use between 80% and 100% for the power level. We normally just use the move speed to adjust the burn level.
Try these out and play with it. If you find a good move speed for different materials make sure to write the settings down and make a list for your preference.