I think you just need to find a small core of players that actively play and share your gaming style, and stick to them (perhaps the Monday night iGTA forum match...what are you doing tonight? ). You'll have better luck over hoping to end up with the same handful out of 300 over and over.
I know I never have any trouble finding iGTA guys online, anywhere from 2-6 at any of the usual times that I can login to Online, and we have folks from the UK across North America and down under as well. A peek at the Snapmatics topic will show excellent results in the shenanigans department.