What sould I focus on?

Hy everyone, (27) Bought like two years ago a triplex and I'm refinancing in a year. Me and my gf who is finishing her Masters this year. And I was wondering what's the best situation for me and my GF in the years coming up. I would really like to have 8 to 9 doors before I turn 30. I know it's not an easy task, but I'm just thinking what's easier buying two triplex or buying in a sixplex. Just for the info I live in Canada/ quebec regon a sixplex I live is around 1.6 mil and a triplex is 800 thousand. I make around 90k per year and a little more with my triplex and my gf is going to make around 80k when she's coming out a school. I know it's speculation right now and I'm just poking the idea around and maybe a some of you guys as better idea of what to do with my situation. Thanks for all the advices and let me know if you need more info.