Michelep,
for me it was simpler to onboard using SNMP to set the values.
check out this post.
http://community.cambiumnetworks.com/t5/cnMaestro/Onboarding-with-SNMP-via-BASH/m-p/45614#U45614
also it should be possible to add multiple DHCP option 43 or 15 in a single configuration.