Cable rafter collar ties
I am remodeling an old house which has a screened second story porch. I would like to remove the 2x4 rafter collar ties and replace with cables to open the room and ceiling. Room is approx 14 by 15 feet. Roof is 12/12 with 2x4 rafters on 2 ft centers set on a 4x6 which is equivalent to the upper plate. No snow load as in the desert! Ridge is a 1x6 which I plan to strengthen and add strong tie connectors at ridge as well as rafter on 4x6 plate. Goal is to have visually open so can see a stained glass window which will be set into the gable end. Rafters are about 12 feet long and have true 2x4 cut showing no obvious deflection,.
How best to substitute cable for existing 2x4 collar ties??? Thanks