Looking for comments/opinion:

I have to install 50 or so exterior lights on a commercial building. Wall is normal concrete block with stucco.

Fixtures are wall mount and call for 4" octagons. I'm going to cut the boxes into the outer block and drill a hole through to the inside, install 1/2" EMT out the back of the box, and go into the back of another box on inside wall. Some lights are on outside of "pilaster", so wall is two blocks thick, but should still work. This will work for the ones above the height of the ceiling grid inside. Others are below the ceiling grid height. On these I think I will still go straight thru, but notch the block on the inside so I can get a 90 in there and run vertical flush with the interior wall so strips/drywall can cover. Going up thru the block and then over into attic is not a good option because of roof construction I think after looking at the architectural drawings. Blocks will be solid poured after.

My real question is will the boxes be secure enough after the concrete is poured? Does this sound like the way to do it? Any other comments in general?

I'm primarily an Industrial contractor. But I have been doing some small commercial
lately. Thanks for any input.