Here is that link for that topic 
Thanks for mentioning about keeping the speed the same. That does make sense, especially if you are running a business and faster == earning more per piece, or charging less. Interesting to note that the latest GFUI proofgrade change (on etching, anyway) goes from full speed more/less lines per inch to half speed, double the lpi. Makes things take a lot longer to engrave, although it does help to clear the little jaggedy forest that you get on a full etch area when running at a lower lpi. Time to cut’em all again, possibly throwing your file into the mix 