i have the 20x30 1 story plans. i want to build 10' side walls and use cathedral or scissor trusses front to back less the end trusses,
would this pose a problem (wall blowout?).
the trusses will be factory built.
No, you should not have a problem with that framing system. I would suggest the 2x6 wall framing and structural sheathing (as shown in the plans). This will tie the end walls and gable end trusses into a structural frame. Also, install clips if specified by the truss company as they will do specific engineering for your local wind and earthquake loads.