Even though they Ben and Duckie are pushing other for the "No. 2 spot" for 1992 born babies in Australia, I think they are in the big eague now and should rather measure where they are in the World rankings.
Also Duckie and Ben have performed well at the Futures level and it is time they contested a few Challenger events in the qualifying. They can spend too much time grinding out the Futures circuir, which is murderous. Challengers have much better facilities, better umpires and more linesmen, more frequent ball changes (akin to playing ATP) and a far better level of player, as well as a much better atmosphere.
Time for these excellent tennis players to step up.
I think it is important for both Ben and James to establish a top 300 spot before they go into the challenger circuit. There is no point in them playing 3 matches of qualifying to gain the same amount of points (3 points) as they would in two matches of a future tournament with a much easier field. Main draw acceptance is the goal and that is why they are sticking to the future circuit for now. Neither of them are really grinding that much, they have both taken considerable breaks after doing well in tournaments and most of them have been on clay so it is not as physically demanding.
You don't actually receive the hospitality of the challengers unless you are in the main draw so Duckworth and Mitchell might be risking a fair bit if they try and qualify. Both players I would think will head home post US Open and play the futures here and if that is the case both may be well and truly established in the top 300 by then which would mean higher seedings among what can be described as easier aussie fields. In terms of their ranking and being judged as individuals I feel you might be wrong because Tennis Australia usually judges a player's performance on their generation and in this case the '92 class is extremely strong so I think it is healthy to compare players of each year class when you have a player like Bernard doing so well and setting the benchmark. As for players born in '91 or '90 I wouldn't talk about their placings among other aussie the same age because there isn't a standout.