Where to find heavier mechs?

[Valden21]

I just got the game on Saturday, and even though I'm loving it, I need to know where to get heavier mechs. Right now, all I'm finding on the Mech Market is light stuff like Javelins and Locusts. What are the systems where I can get heavier mechs?

[Hykril Tynyx]

If you're playing the campaign, then the heavier mechs come into view as you gain more reputation and navigate the map in the counter-clockwise direction (Davion > Capellan > Steiner > Kurita). If you're playing career mode, then the bigger mechs appear closer to the centre (Terra).