If you stake it, allow for growth and watch for strain... Mother Nature will probably let it get a graceful curve. A sharp bend, or tying it tightly too far down can cause a spike to snap of it its own weight (I have an Oncidum hyphaematicum that did that... spike kept getting longer, then the flowers started to develop on branched spikes farther up... and it snapped.
I was VERY sad...) So do watch it and be ready to change strategy if necessary. I have had good luck tying a thin wire near the top of the spike and attaching the other end to the greenhouse or patio roof - so it is supported but the main part of the spike is not stressed by gravity.