Grasshopper scripts.

By email for now. Press buy, I reply with how to pay, and the file comes back to you.

If it does not work, yes: write within 14 days and I fix it, or you get your money back. Try it on its page first, though: it is the same definition you download. The refund policy has the rest.

Yes. Nothing is locked, and nothing in them runs code of its own.

Any job, paid work included. Just do not resell them.

Each script's page says which Rhino it is tested in, and what else it needs.