I think an outright South window would be best, but I understand not having much to work with. I have a Southeast window too. It acts more like an East window most of the year and South during the hottest months of the year (but mine is more East than South when I've looked at the Compass; still Southeast though). I've tried growing succulents and cacti in my windowsill (that's as close as you get!) and still saw signs of of etiolation.
Keep us updated. That is a pretty big (and pretty) specimen you have there.
Planto
