Yes The idea is to keep them straight no matter what you use...I have often used the wooden dowl type as well...I support them a bit though just by putting lite ply cross braces under and over them at a former or two..Just so they cant move around too much...You dont want them to bow or bend if possible...I think they are one of the best type you can use I would only use balsa if it was fairly hard and strait...I like hardwood dowl or arrow shaft or carbon fiber tubes . I have never had them do any damage to a servo or anything else..It seems like they are are one of the old ways of doing things..You dont see them in use as often as you used to... I would just use whatever your kit came with , follow the plan