hey
um the river mouth isnt that good in a SE'ster because it has to come around the heads, but im not totaly sure havent sailed there in SE for a long time. havent sailed the north shore so cant tell you about that, i wouldnt recomend rainbow beach in a SE either, so i dont know what are good waves but if you dont mind flatish water (large chop im and kind of breeze) the i would highly recomend lake cootharaba not far from noosa, not too deep (can just about walk the whole thing , max is 2m i think) and has nice long runs

my 2cents
sorry i cant be of more help qith the waves

kris