Using braces like that is certainly within the realm of possibility.

I'd try and put in a more positive connector than a pair of timlocks, however. Uplift can be a big concern; the the framing style should be able to handle it, just so long as everything is connected well.

Depending on where you are at geographically, post anchorage into the soil may be a bigger deal than anything, to keep the thing from pulling out or overturning. If the wind isn't too bad, you might be ok.

The thing that jumps out at me is there is a lot weight / surface area high up in the air, without a lot of bracing. Wind or seismic lateral forces could really get this thing to twist unless those posts are REALLY stiff.

Certainly will be neat looking, and, looks like you can really can make SketchUp work for you.

Joe