Any advantage of using closed bow-ties over open ones besides the obvious fact you reduce the chance of poking yourself?
Yes, it makes for a stiffer bowtie structure, less chance of damage from birds etc. Gain wise, its about the same as open whiskers, but for the same frequency it can be a little shorter.
Indoors, reducing the chance of poking yourself in the eye can be a big consideration. Styrofoam balls on the ends of whiskers is another option.
The downside is more labor and material.