If the FH can loft 53 mT payloads, you can be sure that is is enough for a Mars program. Many other technologies will be required, sure - but lift to LEO will not be a bottleneck.
Hm, right, that's true. You can send and return people to and from Mars, even settle it with Falcon Heavy rockets. Heavier launchers aren't necessary, I even figured you wouldn't need too many FH launches for a small base. My bad. Sorry.
Wouldn't heavier launchers be cheaper in terms of fuel though? FH can lift five times what F9 can, and uses, what, three times more fuel? If you:
1. Developed full reusability all the way to Mars.
2. Increased the size of the rocket/engines.
Elon Musk's vision for half-a-million round trip to Mars starts to sound less insane.
And even without the full reusability, the rockets themselves are only third of the price. Though FH has the advantage of being built from F9 parts, so an even heavier one might be unsustainable.