I've been pumping calves at shows since the mid 80s. We've never had anything bad happen, but we are pretty judicious with its use. With the natural shape of most cattle now, its not even that necessary. I have the "little red pump", but its probably been a couple of years since I've used at even a prospect show. Just put it down their throat easy - you pretty much have to try to cram it down the "wrong hole". Pump them very slow - we usually used a combination of 7UP and water. Never any more than maybe a five gallon bucket full that I can remember.
Your best bet is using feeds that will swell. There are some alternatives to beet pulp now that have more nutrition to them for long term feeding. Several manufacturers are starting to make high bulk feeds that are still pretty high in protein and fat (Acco, Kent Feeds - First Rate Winning Fill). I'm not an expert on their use, but they might be worth looking into for long-term feeding. Certain hays work better than others also. Whole wheat hay works pretty well I think.