Aluminium Profile Type Router - Initial questions

[CNCRY]

Been busy this week sorting out a ply threaded board, used 75mm spacing as suggested rather then 100+
I then have a second piece of MDF on top with holes but its not glued, just bolted down at various points currently.
The M8 bolt fixing is working pretty well, using simply bolts and washers to clamp the edge, however without gluing the MDF spoil board I can't surface it accurately which is an issue, just wondering if there is a better alternative to gluing ... screwing with slightly countersunk holes?

So much to learn about fusion 360 CAM still - managed to make my first aluminium part! Simple pocket toolpath and cutout, but I was pretty happy with the finish, not that I have much to compare to, just it did it first time with no issues.
Couple of sprays of WD-40 but used 17,500rpm with 1mm DOC, 6mm 2 flute end mill.

It's a um... coaster?



May give the Aztec calendar a go Jazz , is there any specific high quality STL file you have for fusion 360 - as a few various ones out there I've found?

Also, does anyone have any suggestions for the best way to face a surface that fits in an ER-20 collet? I've seen flycutters etc mentioned but most are too large - any recommendations?

Ryan