I don't think this is a good idea. Builders can ask in /ch g or /ch l at spawn or /pm a mod. This will just be a hassle for staff members because they have to moderate one more chat. Builders barely know how to change channels as it is, so they are going to need to ask how to get into the help channel anyway. Might as well answer them in local spawn chat.
-1
If you decide to do this, you would have to make a town called "help", (85k) then buy the town chat (40k) totaling in 125k. I did this to make a trivia channel, however its rarely used.