Sounds perfectly fine to me. I don't know about grammatics, but it's definitely commonly used by native speakers. And language forums seem to agree.
So am I correct that תרצי in this sentence is not functioning as a future, but in a modal way in conjunction with אם? I.e., the אם signals some measure of doubt that the envisioned condition (viz., the addressee wanting) is true, which calls for the imperfect/future. I.e., the imperfect is used here not with reference to a future time, but in a modal way. Is that right?
It is in the future, as in "if you will want me to go home, then I will", but it's also a common way to express the idea in Hebrew without it necessarily happening in the future. Unless some other time indication is present, the future starts now.