400 characters seems reasonable. However, what if we let it be user-defined?
CHECKBOX Split messages longer than [number field] characters up.
CHECKBOX Split messages up near [character field].
(Character field would actually be a number. 32 would indicate it would fall back in the sentence to a space and split it there.)
(Checkbox means it can be enabled or disabled. So, it wouldn't split it up near a specific character if it is unchecked.)
(I suggest keeping that space, or other character, in the previous line. A space can be safely removed, but if someone chooses a period or something else, it would look weird removed.)
Parse lines every [seconds field].
(3 seconds means it performs a 3 second delay before sending the next line. Control break would halt all of these. I would suggest limiting it from 0 seconds to 60 seconds.)
