Check current tmux pane sizes

When dialing in split percentages for a layout config, check what you're currently working with:

tmux list-panes -F '#{pane_index}: #{pane_width}x#{pane_height}'

Output looks like:

0: 211x72
1: 170x50
2: 85x21
3: 84x21

Use these to reverse-engineer the -p percentage values for your split-window commands.