Have you tried contacting expired listings. How I used to pick up bigger listing is I would contact other brokers at other companies and ask them about their current listings. Then I would throw a question about hard listings that they have missed out on. Sometimes they will tell you about all of the available properties that you did not know about. Like where I am located there was a $26,000,000 oil refinery and I contacted the broker and asked have they had any hard leads and I got all of the specifics. He said no so I started contacting oil companies who were either looking for or just purchased that same type of refinery. I found a broker at Exxon and we started to do the deal to purchase this facility. But a Russian company came and purchased it cash after our initial meeting. So you never know what you may come across
I always went big because you will go down a worm hole looking for information and you end up stumbling on leads or listings.