Proper grammar means shit all in English, unless you're worrying for a specific style, in which you follow the grammar rules for that style.
Standard English has such a long list of weird and contradictory roles with nonsensical exceptions, that in every day English, getting your point across in communication is better than trying to follow some more arbitrary rules.
Which become even more arbitrary as English becomes more and more a melting pot of multicultural idioms and slang. Although I'm saying that as if that's a new thing, but it does feel like a recent thing to be taught that side of English rather than just "The Queen's(/King's) English" as the style to strive for in writing and formal communication.
I say as long as someone can understand what you're saying, your English is correct. If it becomes vague due to mishandling of the classic rules of English, then maybe you need to follow them a bit. I don't have a specific science to this.
Digitising skills be a given but as long as it has a high quality audio jack you can do it through that.
Recording onto cassette is different though because doesn't that need a specific writer head?