Yes they do have quite long necks- thats a good thing though as it gives you plenty of room to cut them/shape them/sand them down to the correct shape and size that you need. My advice is to look at the head you are replacing- if it is itself a seperate item then try and shape the Hornet neck area to match it so the fit will be quite similar.
In a couple of instances I've had Hornet heads where the necks appear too thin for the figure- so in these cases I tend to add something like a scarf from Magic Sculp to disguise it.
That being said I've certainly had quite a few instances where the Hornet heads fit with only a minimal amount of work shaping the neck area. You really can't say what you'll have to do until you know what figure you are going to attach the head to.
But be warned- if you use one Hornet head you'll be hooked on using them

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