When to rivet fwd top fuselage

When do you rivet together the ribs that hold all the electrical and avionics? These are the upper forward fuselage just behind firewall.

Do these ribs have to be riveted before you hang the engine for strength purposes? I would think not. How about for cowling fit?

Do they have to be riveted before installing any electrical components? I would think so.

My fuselage, canopy is finished. Basic wiring for lights, sticks is done. Engine is ordered and coming soon. Is now the time to rivet these parts so I can start installing components?

Will there be any surprises if I rivet them now?
Pedals are in, brakes, etc.

I had the three ribs and sub panel all riveted together and was able to install and remove, also had the fuse on a rotisserie. It made it easy er...to get to the floor area to do all the fuel plumbing and wiring like this, I had the sub panel clikoed on while I had the engine mounted to do the cowl, then removed all this many times to complete items, I would wait till all your wiring is done. already had to remove CP stick and crawl under dash to install oil separator mount nuts on firwall.....don't want to do that very often ;-)

You can install them now and rivet. I just went through this and it is no problem to do wiring with the sub-panel structure in place. After the panel wiring is complete, I will be wiring up the Infinity grips with the associated relay board.

Do all the wiring behind the panel before installing the top fwd skin, of course.