Intuitively, showing both the upvote and downvote count would display the full information. The total and the percentage can be derived from that (and yea humans are bad at maths but you'll be able to estimate well enough probably).
I also like showing both counts separately so that a +50 -10 post doesn't appear equivalent to a +100 -60 post.
Could you perhaps show some screenshots of how the different options would look? Preferably on both mobile and desktop. I think that would make it a lot easier to choose.
It’s also an easy way to show new users one basic front-facing feature on Lemmy that is different from Reddit - which is a good idea on its own, but especially because Reddit used to display upvotes/downvotes this way and then removed it entirely, probably for manipulative reasons.
It’s good to be able to customize, but better to have the default option be an improvement over the alternative. Even more-so when the change isn’t jarring.
I remember when reddit removed the simple upvote + downvote and added "vote-fuzzing" and upvote percentage. Everyone hated it, but there was no alternative to switch to.