I've always avoided Worm staves because of the wonkiness of bar swapping.
SPC staves are better, anyway.
The reason is that healers will run 5p SPC plus another 5p set. The SPC is always there, but the other 5p set changes depending on the group's composition and what the other healer is running (if you're in a 12-man trial). For example, my healer carries around a SPC set and five other sets that I would pair with SPC (Worm, Infal, Twilight, Goss, Sanctuary).
Since the SPC set is the "constant" set that you'll always have on, it's best to have it occupy the most difficult-to-acquire slots, since you only need to farm those slots once. Weapons are by far the hardest to acquire. Armor in ideal traits is in a distant second. And jewelry is by far the easiest pieces to acquire because they have fixed traits.
So you should have 4x SPC armor, a SPC destro, and a SPC resto. And then your other sets like Worm would be run as 3x jewelry and 2x armor. Luckily, there are two named SPC destro items: Molag Kena's Touch is a Powered (great trait for pure healing) Lightning staff (so you can use it to proc Infal without swapping to resto), and The Unbroken is a Sharpened Inferno staff (a good choice if you prefer to do a lot of off-DPS in 4-man dungeons).