Minimum Rocket Payloads Issue

[Forblaze]

I'm on Gleba, producing agricultural science packs. I have a platform bouncing between nauvis and gleba and set to import 2k agricultural packs from gleba. If it doesn't have 2k available, I don't want it to wait indefinitely for those 2k science packs. So I can use the time passed or activity condition instead of just full cargo to get the platform to leave gleba, but since the rocket needs to be full to launch I may be leaving behind, say, 900 science packs. I would rather launch those 900 science packs than leave them to rot on gleba.

I see I can configure a "minimum payload" in the orbital request UI, but the problem is that the rocket seems to launch as soon as that minimum is reached. So if I set it to 500 and I have 1900, it's launching 3 rockets of 500 science packs and leaving 400 instead of 1 rocket of 1k and 1 rocket of 900.

Is there a way to do this better?