One of the first thing you need to make sure of when milling aluminum at speed is chip clearance. Unless you are set up with a good misting system (fog buster) then you need a good chip clearance system if you intend to cut aluminum at anything close to those speeds. I have has the same spindle you have for over a year on the Shapeoko and it is not really set up for that aggressive of milling in aluminum. The DOC will not be much greater than .25 at most if you are lucky. The main issue is the 400W spindle does not have the power to keep up the RPMs under heavy load like that type of milling will do. A dewalt 611 or a .8KW VFD spindle is far better suited for long term aluminum milling. You can chek out my thread here Production level aluminum milling with .8KW water cooled VFD - #35 by EricDobroveanu for an idea of milling with the X Carve in aluminum on a larger scale.
I am by no means an expert, but my experience of milling aluminum on both the Shapeoko 2 and the Carve have allowed me to produce some very good result on some complex parts.