[DaninVan]

I'm probably too late but don't notch the rafters! I'm not talking about the birdmouths, I mean those notches to receive the horizontal strapping. They substantially weaken the rafters and if done on a house roof would invite a total rejection by the Bldg. Inspector.
The strapping gets nailed/screwed onto the top edge and the resulting gaps on the ends are covered by the fascia or bargeboards applied to the outside rafters.

 

[DaninVan]

An alternative to the above is to toenail 2x4 blocking between the rafters at either 16" or 24" centers, basically to support your sheathing edges and midway points. In any case don't notch (botch?) the rafters!