Looks fine. I think you could get away with running 1/2" emt if you're only running a fan/light combo (smaller radius bends) but if you can squeeze that shepherd's hook in that cavity above the rafter then go for the 3/4 for the easier wire pulling. Just make sure your conduit doesn't exceed 360ð of bends between the pancake box and the next termination point, be it a junction box or your panel.

How do you calculate that 360 degrees? The shepherd's hook looks as if it uses 270 degrees, so I have only 90 degrees left. I will need that to go from horizontal to vertical, then to a junction box, but I guess I can't have any deviations in that vertical run (to go around other obstructions, for example).

Does your SIP have wiring channels in it?

I don't think my SIP has wiring channels - it's for roof only. How would the SIP company know where to put the channels? In my drawing, I would consider the little triangular area above the beam a wiring channel.

WHY would you need to change the wire later???

IMO a SIP panel home is a ROYAL P-I-A to wire, even for a professional. I would imaging it is a nightmare for a DIYer or someone who has never done one before.

Over the years I have done several homes like this and two barns. These days I simply turn them down. Let someone else make the $$ on a PIA job.

Petey-
That's why the walls are conventional construction, because of the difficulty of wiring a SIP wall. Only the roof is SIP and the only wiring there is what I've shown here and in another post about low voltage lighting. And, I'm not doing it myself, I have a contractor, but I need to decide what's reasonable to ask him to do. He has seen my illustration (after I started this thread) and says that that's fine.

I finally got the scoop from the electrical inspector in my new location. When I asked what NEC code level they require, he didn't really answer, but he did say that AFCI breakers were required almost everywhere. He then said that they are not required for the smoke/CO2 circuit, the microwave circuit, the refrigerator, or "others like that". What would "others like that" include? AFCI breakers are required in bedrooms, living and dining rooms, family rooms, etc. etc.

Article 210.12 that covers AFCI requirements has this exception:

Exception: Where an individual branch circuit to a fire alarm
system installed in accordance with 760.41(B) or 760.121(B) is
installed in RMC, IMC, EMT, or steel-sheathed cable, Type AC or Type MC, meeting the requirements of 250.118, with metal
outlet and junction boxes, AFCI protection shall be permitted
to be omitted.

You know, buying a copy of the code (or the handbook) is going to be a very tiny part of your building budget and may be very handy to you.