Regarding possible time interval: I don't see any problem. The timer simply go ahead the end with no stop, if I need to cut some parts there are a lot of free subtitles application which allows to make adjustements.

The stenomachine trigger is the real hard problem to solve: I don't know if API are provided, I have to ask.
The stenomachine has its own application with convert keys combinations in words. This application has a very simple Output utility which allows to tranfer what you are writing into any kind of Text Field, everywhere there is a blinking cursor.
So I can write into the Notepad, a google search edit field, here in this form, etc.

But they are just words, numbers and some special character like # % $, etc. Stenomachine has no function keys, has no CTRL ALT SHIFT.

For this reason a different kind of approach must be studied: for example a second timer that every 0.01 seconds check what I'm typing and if it finds a shorthand like "crc1" for examples, it change fonts, if it finds "crc" it goes to a new paragraph and add TimeCode.

What do you think?