Very few ppl sail around Lakes entrance area. I only saw 1 other windsurfer when i was there fore 18 months and that was at Marlo. The estuary at Marlo might work but its gunna be a short run to the sandbar.
Eastern beach might be sailable but unlikely, the shore breaks are super heavy along the 40 mile beach once they start breaking.
I agree with sailquik, paynesville will give you options out at the point but bring booties because there are lots of mussels in the water, especially near shore.