Looking for some help understanding the code around cathedral roof design and collar tie requirements when not using ceiling joists. 

im trying to draw up my plans for the city but can’t really make sense of the code.

id like to keep the ceiling open for the most part, with storage overhead on either end. 

I can size the rafters and ridge board but how many collar ties and where to locate them eludes me. 

I’m considering spending the money and just getting an lvl, ridge beam. In this case do I require any ceiling joists or collar ties to fight spreading?