Resize your Terminal in Mac Preferences to fit your needs:
Open Terminal with Spotlight (⌘space, enter 'Terminal') and open Preferences (⌘,). In the Window tab, look at the Window Size, Columns & Rows. The values are often 80 and 24.
Optionally, resize your window to fix your desired new size. Pause and think, 24 lines, how wide is a line? OK, how many do I need?
Increase column size if when you both create a new tab or new window it is not the same size as your desired size.
Trial and error, just attempt to keep your estimates close and it will be brief. Similarly decrease if it is too large, for example, on this 1920 × 1200 scaled display the following is great for me: 130 & 40
Test your new setting by opening a new tab (⌘T).
Place your window over the previous one, is it the same size or close enough for you? If not keep resizing, until it is.
Open a new terminal window also (⌘N) and do similar.
Now consider using a window management program, I recommend Spectacle because it is free as in free beer and freedom: https://github.com/eczarny/spectacle
You can then use the following to move windows quickly while a window is selected: ⌘⌃→
This places the window in the top right corner 1/4 of the screen, left works similarly. If you also hold down shift it will place the window below in the 1/4 half of the screen: ⌘⌃⇧→
Plenty more options are available, enjoy!