You apparantly think I only fly foamies --
Not so - I am familiar with this particular model
It is very difficult to get weight in line with it's size.
Also - I am more firmly than ever , convinced that weight is the prime cause of problems like this
You can twist in tip mods - add flaps -etc.,
None of this will make any notable difference .
If the model is straight and balanced -then speed will keep it controllable .
Slow it down and it will trip you up.
Theory is fine -and I do understand the theories put forth.
In this case tho - we are caught with simply a high wing loading.
You might want to go to Kirby Chandless'web site and look at the comments made by the team on wing design.
The info there is very applicable to models .
As for the foamies
Did you ever try them ?
They can provide a lot of info , applicable to larger craft