It's important to understand that the precious metals configurations on Cisco WLC's only define the maximum allowed QoS treatment WMM queue and DSCP value.
In Meraki you can set QoS rules per SSID but you don't have a preset limiter.
The best way to accomplish this is to make one traffic shaping rule on the wireless -> firewall & traffic shaping page that matches any subnet with a custom expression and then choose the correct DSCP value. You can't set the 802.11UP value anymore but I believe they are correctly derived from the DSCP value.