sorry Antonio, I kind of skimmed what you wrote and didn't realize you didn't have access to a leg press. I have seen some crazy bastards lie on their back in the smith machine and use it like a leg press.
I don't think the leg press really gives me the glute stretch that say a stiff legged deadlift does...have you tried those? off of boxes etc? There are many variants of squats and deadlifts that can be done that are far superior to the leg press (IMO).
Front squats, zercher squats, get your hands on a manta ray for cheap and that's another variant.
If you've got a power rack you can do concentric squats. Various GM's, seated, standing, arched back.