wji, I would go with g-max. It's not that hard to build signs, But I will suggest that it is more harder to learn how to use gmax, then FSSE. Animations could be hard, that's if plan to do so. If you chose to go with g-max check all the toturials you can get a hold of. Or you can just buy FSSE, and easilly upgrade your'e scenery. G-max is meant for building what you want, then putting it in the flightsim. I would recomend from not knowing your level in g-max, is to just stick with FSSE.

Gmax is a designing program, and FSSE is a scenery enhancer. Which has all the objects allready built.