For a 42" table surface, a betting line 6" from the rail leaves ~30" of play area. For a 44" surface, a betting line 7" from the rail also leaves ~30" of play area.
6" allows four rows of stacks between the rail and line. If wanting 5 rows deep, you'll need it at 7.5" from the rail.
A triangle of stacks five wide is 7.5" across at the base, and 7" deep.