Congratulations on the S500!
What is the exact kind of work you are doing here? I’m saw your posts asking about 3D finishing, and I see sort of a trend in your tooling list for long-reach/small nose tools. Are you doing a lot of 4th axis work? Aluminum or harder materials?
The most important key to running a BT30 machine is keep gauge lengths as short as possible. One of the problems when you get into things like milling chucks, shrink fit, and hydraulic is that the companies who make most of those do not understand this fundamental aspect of BT30. I’ve tested a number of milling chucks (including Big Kaiser’s new compact BBT30), and have never been impressed with any of them because they tend to have massive gauge lengths. For roughing applications, you would do well to live with Weldon flats (or using a green grinding wheel to put a flat on the carbide yourself) and run Maritool’s super stubby side-lock holders.
Finishing cuts are a different beast because the side load on the tool is much less, but gauge length is still a major factor. I’ve settled on Maritool SK16 for every finishing end mill in my turret. The concentricity is great, the vibration dampening is great and the flexibility of having one collet system is totally worth it. I would also look at Big Kaiser MEGA collets, which are extraordinary, but way more money. Rego Fix is the ultimate answer if you can afford it. ER16 holds all my drills/taps/reamers, with a couple of ER25s around for bigger stuff.
I would hold off on the Schunk hydraulics for now. Even fussy Speedio users are getting great surfaces with SK. Hydraulic tends to be way psst the cost:benefit curve’s inflection point.
The face mill arbor is way less important than the selection of a face mill. What are you looking to do with it exactly (my belief is that face mills are really for finishing in these machines, not big material removal).