Yup, I certainly remember the Brontosaurus Burgers and the Ribs
Course that kinda dates us huh
I don't like being ambiguous but without having a sketch in front of me, my structural design manuals and a calculator there is no way I even want to contemplate designing someone else's trusses. With that said however, when I did mine a lot of it was done whilst sitting on an upturned 20 litre fuel pail and simply studying the problem visually. Once I had that done, the design problem was much easier even though the math was kinda onerous.
You already know what and how you want to do it, I suspect that you are probably close ... best be safe if you can. Do you have access to a College design course that the question could be posed to? I would feel much more comfortable if they ran the design through the truss stress program (we used one called STRESS way back when -- used punch cards -- remember those?? ) to see what the loads would be like, how much deflection the truss will withstand as well as torsion and the compressive forces that will all come to play especially on the cantilevered portion. That is where my concerns would lie.
If you look at the Cantilever options in this document .. Maple Valley Truss
, you will see what I mean.
Your cantilever dimension is going to be about 8 foot. So you are going to have to design a sub truss within your truss as well as use continuous lateral bracing to tie them all together. That sub truss would have to be constructed in the area of the overhand -- as designated by the cantilever dim
in the sketch above. You might get away with building another W-truss within that area.
The CLB will reduce torsion and strengthen the framework so that the the amount of deflection occurring from compressive forces will be lessened because of the additional chord and webbing material. This will provide the strength needed to withstand the snow load, as well as the wind load. How you tie your trusses to the load bearing wall abaft of the cantilever will determine how well the truss will withstand some of the wind loading.
You will have to consider how you are going to anchor those trusses. I would think that a continuous saddle bracket would be a definite option which would allow for through bolts and square washers. By using say a saddle bracket you will be adding to the structural integrity when it comes to vertical uplift from lateral wind loading.
Oh an afterthought. I would definitely be using plywood gussets as the plywood gussets will resist torsion from lateral wind loading whereas the galvanized expanded sheet metal gussets will not.
Other question ---- the walls of your shed -- western framing 2x4 walls or cinder block?
That is about all my tired brain can handle at the moment .... I hope I made some sense