Does Airlift 1000 w rear spacers work?

[Choate]

I’m sure this has been answered but I couldn’t find it. I have 2” rear spacers on my truck. I think I found that to run the airlift 1000 set up I could drill holes in my lift spacers to run the line for the air lift helpers but I’m not sure that’s a good idea. My question is what’s the normal or best way to keep the truck that’s lifted (3.5” RC front lift and 2” rear spacers) level from sagging in the rear if I towed a light load like a John boat and trailer or a utility trailer and golf cart