I believe the icon size is automatic. If you have a lot of items in your stack, then the icons will be smaller. If you only have four or five items, then your icons will be huge. You can check this if you drag your entire Application folder onto the Dock as a stack and the icons are definitely smaller.
Yes, I have also noticed that there is no Fan option if your Dock is on either the left or right. The "View As" option is not even available. The Fan looks like it's only available of your Dock is at the bottom of your screen. That took me a while to figure out.