proper loading is in the eye of the beholder
But -in the size range of say -- 1000 sq in
For a good aerobat
28 oz ft is very good and easily done
Problem is the rash of absolute rolling stones on the market --they look like aerobatic models but are not in the right power/weight/size .
Our personal taste is 25 or under for that size-also easily done but no BARFS will do it .
once you jump to about 1500 sq in - then 30 oz s is very acceptable to most flyers.
The size and loading are really on a steep slope in this size range.
a little 25 powered model - should be down in the 15 oz ft (assuming 350 squares) at least!
Some very tiny aerobats -notably , small electrics of about 300-400 squares work bestonder 10 oz ft and my own foamies are under 5 oz ft.
pretty steep slope, no?
models of 1700-2000 squares cn be in low/ mid 30's and still fly quite well .
again - there is a lot of personal preferrence here --