According to your initial request I think further clarifications are needed. 
What devices do you manage? Access points only? Or do you have also Meraki MX and switches?
 
I am asking, because you say "but I need a DHCP option 150 to be configured on the Meraki wireless".
 
The DHCP options are set on the DHCP server. So if you have a Meraki MX or L3 switch which acts as DHCP for the Voice vlan - then you can set the option in the Meraki. Otherwise, if the DHCP is still a 3rd party machine (Windows, Linux, Infoblox, etc.) then you have nothing to configure in Meraki.