Like you thought, it depends. Doritis spikes naturally grow straight up, without staking, but Dtps, while usually more upright than Phals, tend to droop more both because of the tendancy of phal spikes to droop, and because the phals impart larger flower size making the inflorescence heavier.
I agree with Rosie's suggestion of a loose tie. This provides some support, so the flowers are up where you can enjoy them, while still allowing the inflorescence to display its natural grace. (at least for a potted plant. for mounted plants, letting them hang brings the flowers DOWN to you)
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Evan
| it's not my fault, the voices tell me to buy orchids
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