You know, I did give it some thought, to use that method. Stick in a long pipe, and wiggle it around. My trailer is 14 x 65 feet long, so it owuld take three lengths of pipe. I played with the idea of dumping the insullation through the center of PVC pipe. I wouldn't want to be 20 feet out from the end of the trailer, trying to hold a length of pipe 10 feet off the ground..... though it is a funny thought.
Your lengths of iron pipe to guide the tip, now that might just work. Back it out, and then unscrew a length off.... that could work.
Like you say, it's not possible to get even coverage, but it would be a lot better.
I worked with fiberglass some years ago, on a temporary job. I worked one shift, and couldn't get my clothes to stop being itchy. Even washing them twice. I went back the next day and resigned. Very politely, too. I ended up discarding the clothes. I'm not happy with the idea of fiberglass.
My heat bill last month was $230, and that's with a 90% plus furnace that I installed earlier t his year. And a setback thermostat.