Have a look at this site:
http://www.ef-uk.net/data/wcl.htm
This takes into account the better weight carrying capacity of larger wings.
Personally, at 1/6 scale I really like 16 oz./sq. ft. Much lighter is a challenge in any wind, much heavier is less forgiving. Remember too, that biplanes can handle less wingloading for a similar handling to a monoplane - 24 oz./sq.ft is great on a sport plane, less so on a scale bipe.
Maybe you should build another Nieuport and try to get the weight down. I have a 1/6 N.11 at 3.5 lb, (14 oz./sq/ft) and a 1/5 N.12 at 8.75lb. (17 oz./sq.ft), both of which take off easily - apply power and the tail is up and the rudder is effective before much swing can develop.
Just my 2 cents.
Martin