what is the difference between the following?
I'd rather you went home now. I'd rather you go home .
It's not actually simple present - expanded, it is:
I would rather you went home now.
It actually form a mood, the subjunctive mood, which is rather fossilised and dated in English but nevertheless has its uses. 'would' on Collins
As for:
- I'd rather you went home now
- I'd rather you go home
I don't really parse them as having any difference; I can't think of any situation where they two would have different meaning, unless it was in the following type of exchange:
But even then, it would only be a rhetorical preference. I'll note that traditionally, the infinitive form (ie go) has been used with the subjunctive - for instance, I'd rather we be quiet now, rather than I'd rather we are quiet now, which is questionable at the very least.
In short: you've used it correctly. For present tense desires/preference, there's no difference I can discern between past/present in the subordinate clause, at least not with regard to everyday usage.