I've done it... I'll be writing it up properly next week but...

https://api.v4v.app/docs#/v4vapp/new_invoice_hive_qrcode_v1_new_invoice_hive_qrcode_post

curl -X 'POST' \
  'https://api.v4v.app/v1/new_invoice_hive/qrcode' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "app_name": "live_test",
  "expiry": 600,
  "hive_accname": "brianoflondon",
  "message": "live testing with a unique message",
  "hive_amount": 1
}'

That will get you exactly 1 Hive with whatever message you put in (and only that message). You can use hbd_amount to HBD or even usd_amount to get a USD value as Hive.