7.62MM dot pitch = .3"
character matrix of 5x7 = 1.5" wide by 2.1" tall
Smallest letter is then 2.1 tall
39" display height allows max of 14 rows of text
77" wide allows 42 characters wide
with 4 lines text get 9" tall x 11 char wide
8 lines text would get 4" tall by 23 char wide