Salam,
I'm a Canadian Pakistani, want to buy an apartment in Bahria Town overseas block Karachi.
What do you suggest?
Why don`t you purchase a land and construct according to your requirements? Because you are not at the exact location so there can be some serious issues if you buy without visiting. You should hire any construction company and discuss after buying a plot. If you feel that it will be late then any real estate agent in Bahria can be helpful for you to buy an apartment as per your requirements.