If you have the opportunity to cut this project or a similar one with LOTS of retracts/rapids, let me know what difference you see between the estimated time and the actual cutting time.
I measured the actual cutting time on a project of mine this week-end, and the Fusion360 estimate was within 10sec of the reality, BUT it had very few rapids, so that configurable value had no weight at all.
Estimated cutting time aside, if you haven’t already I think you should take a look at Winston’s recommended GRBL params (which happen to be the defaults now in CM 5.x) the machine just feels more “alive”, and rapids can be up to 10.000mm/min, which in a project like the one in this thread, will certainly help a lot.
EDIT: sorry, just saw in the other thread that you are aware of the 10.000 rapids in CM5. Ignore that last paragraph.