Is there a way to increase the size of the viewport other than dragging the Parameters panel below it down (it will only move so far)? In some apps you can open it as a floating window.
It depends on what version you are in. In the standalone, you can do this. In versions of the plugin you can not for most hosts as an architecture limitation.
I am using the standalone Mocha Pro 2019. The only way I can enlarge the viewport is to make it a floating window. The Parameter panel has a limit to how far you can drag it down.
You can drag the parameters window and all other windows out of the main Mocha window, you will be left with only the viewport.