The standard paper punch cards of that era had eighty columns and twelve rows for a total of 960 bits capacity. But a programmer needed access to an IBM 029 keypunch or the like and this wasn't something to be seen in anyone's home.
Paper tape would have been a better idea for the Kenbak-1 as tape punching Teletypes were fairly common at the time. And it was a fairly mature technology that had been in use for many decades.
See the "ppt" program on your favorite Unix:
Code:
| o o. oo|
| oo .o o|
| oo o.oo |
| oo . o |
| oo . o|
| oo o. oo|
| o o.o o|
| oo . o|
| o . |
| ooo . |
| oo . o|
| ooo . |
| oo .o o|
| ooo . o |
| ooo .o |
| oo . o|
| ooo . |
| oo .o o|
| o . |
| oo .o o|
| oooo. |
| oo . o|
| oo o.o o|
| ooo . |
| oo o.o |
| oo .o o|