Friends of mine who toured regularly in the US a few years ago said that their approach was to engage a good, well-reputed visa lawyer and pay them to get on with it. It wasn't cheap, but compared with the cost of losing paid-for flights and a month's work fees they considered it good insurance money well spent. It always worked, and a professional in the field is fully aware of latest bureaucracy changes, necessary timescales, and most importantly has a good trusted working relationship with the bureaucrats. Can't see any reason why this approach shouldn't work in the opposite direction. It's when people stick their heads in the sand, think they can cut corners, slip under the radar, it won't apply to them etc that things fall apart. None of which excuses ludicrous, offensive, inappropriate bureaucracy, regulations and attitudes on behalf of those who ought to be out catching real criminals to fulfil their quotas.