I didn't invent spread myself, it's how it's done in all other sports for 3 times my age now :P
It's why I don't really feel like it's a good idea to make my own solution for this like giving them whole numbers and stating what happens in case of a draw since it's quite of an established standard and everyone who knows betting expects it to work like this, though I do realize that my users have no clue about gambling which is why I've added this description in which I'm stating points needed for a draw. Anything more is a win, anything less is a lose.
I'm stating points instead of rounds because those are not always equal.
In any other format than BO1 each map won is 3 points, no matter the amount of round played, except for GCs which give winning team 2 points and losing one.
And there's always (pretty poor) knowledge base :P
https://saloontf.zendesk.com/hc/en-us/articles/202946962-How-does-scoring-work-on-Saloon-tf-