Sorry to burst your bubble Toronto people, but if GAs aren't available by Breathe/Boots presale, I DOUBT they would be available in the general presale.
I bought Toronto GAs in the horizon presale and mine were 'GA21', i.e. 21st section allotment, suggesting they had sold quite a few sections already before those.
They only allot a certain number of tickets for presales and leave a good chunk for general onsale. They never put everything up for presales.