If there was any such trick in recent times, then majority of forum members would have LTF Emeralde PVC. It would have been abused so much that loophole would have been patched up by bank.
You are very late to the party.
Sapphiro visa LTF is anyday better than Rubyx LTF.
Keep using your Sapphiro as much as you can, you may get LTF Emeralde PVC offer. Though it's not guaranteed but many got this way in past.
Other way is having high TRV with bank and then ask Emeralde PVC LTF. Choice is yours.