[mgatepi]

You can definitely reduce the thickness by using a HSLA steel. (High Strength Low Alloy) If I remember correctly the angle iron material is extremely low carbon with a Yield strength of about 35KSI at best. So going with a HSLA 60 or 70 steel, this will allow you to reduce the thickness by roughly 40% to 50%. You may be able to do some things with the shape of the steel to even reduce the thickness more. Such as formed ribs etc. if space allows