yes, a 3.3 safety factor is more than enough with a braced tank. Safety Factor is an industry created measure of glass safety, the industry recommends 3.8 for a rimless unsupported build. There are no guidelines really for supported tanks. Many people have chosen 2.2 as the low end safety factor because it relates to other known safe builds at what we have been comfortable with. I personally have a tank that when built people were very skittish about it, it has .375 inch glass and a fill height of 24 inches. Mine is only 48 inches long though so I have a bit more wiggle room on safety factor as compared to you. A lot of people think 3.8 is overkill either way but meh.. when it comes to wet floors to each their own.