OSB can't just have an unsupported seem in free space. The instructions you are looking for will be in the sheathing manual (i.e. Huber), not the truss manual.
Don‘t do it.
The gable end wall needs to be reinforced with more studs turned 90* from the flat ones there now. Simply nail the additional studs flush to the outside and to the sides of the flat ones. Depending on how big the gable is it will need some bracing perpendicular to the gable. Nail a board across what you did above and then brace that to the truss system. Check with the truss people for details of your building.
You will also want to be sure your sheathing overlaps the joint of stud wall and the end truss. No joint in sheathing over the joint in framing.
All the above is one of the differences between a floppy crappy building and a stable strong building. It might be $150.00 extra cost and an hour of your time.
