I took the brace off my 65 before filling it, and replaced it with 1/4" acrylic, attached with nylon bolts and epoxy.
Glass would probably be stronger and cleaner looking, but might be overkill.
Doing it full could work if you attached the acrylic, then cut the original brace. However, I'd support the tank well with angle iron and clamps before cutting the original brace.
What about replacing it with stainless steel cable? If you could come up with a good way to attach that to the rim on each side, it would be a great solution that doesn't require cleaning, casts no shadow, and doesn't get in the way.
Nate