Personally I never eliminate a horse just because it has a wide barrier. Whilst it DOES affect the winning chances I personally believe that most punters overestimate the disadvantage and hence you can often get good value on those horses. I simply adjust my required dividend based on the barrier and then bet if the horse is paying more than that dividend.

In MY OPINION the "don't bet on it if it is wider than barrier X" is a symptom of the "look for the winner at any price" attitude rather than looking for the value in a race.