I'm actually not using 4x4s at all. If this forum wasnt so open to everyone on the web, I'd share most of my trade secrets.
I thought of a way to keep slim led downlight drivers in one location in attics which makes it easier to do warranty calls on bad drivers.
I'll be using extension cables from now on and keep all the drivers on a piece of wood in the attic, pre-assembled and wired in my shop.
I realized chase nipples are the only way to go to be able to remove a single driver that's between any 2.
I'll have 10-12 drivers in line using chase nipples.