@WVvet
I just thought of something you need to be made aware of. Carto tanks get their airflow from the 510 thread so you need to use mods that have air cuts on the 510 connections. The Coolfire z80 has these air cuts, so no big deal. But the Z50 doesn't.
There are a few ways around this problem, but the easiest one is to use a 510 heat sink that has airflow cuts,
like these. Using a 510 heat sink w/air cuts on the Z50 will give you the airflow you need for the carto tanks. Of course, the down side is that it will add a little more weight to your setup and will add height to your tank.
The 2 other solutions require modification...
1) Use a dremmel/rotary tool with sanding disk or cut-off wheel to cut a couple/few airflow slots in the Z50's 510
2) Use a dremmel/rotary tool with sanding disk or cut-off wheel to cut 2 airflow slots in the bottom/base of your carto tank right next to the 510 airflow holes.
And actually, look at the Z80 pics, I see the airflow cuts that go toward the 510 thread don't actually go the whole way so there is a chance you still need the 510 heat sink when using the carto tank on it. Not sure.
Lots of mods these days don't have airflow cuts because no one really makes 510 airflow tanks anymore. Airflow is usually on the side of the tank (top or bottom).