Hi @Shadius
Correct - you can't stack these models together.
Do the MS150's you've purchased have the fixed 10Gbps uplink switchports? If so, i'd use those to connect to your MS350's if you're deploying them in the same cabinets/locations.
If you can't connect via 10Gbps then simply ether-channel a few 1Gbps ports on your MS150's and connect again to a bundled ether-channel on your MS350's.
I'm making assumptions that you're locating these devices in the same locations and of course have spare switchport capacity.
Darren OConnor | doconnor@resalire.co.uk
https://www.linkedin.com/in/darrenoconnor/
I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.