Oh boy!,the crap I'm going to get from this one. What's your lowest, tightest crawlspace? Hottest, tightest attic job? This is pretty much a serviceman's site,so let's hear from some crawler's and tinknocker's.
Was running flex duct in a 30 inch crawl space with webs from floor to ceiling. I used a broom to clear my way and it came out looking like a giant Q-tip.