This project sounds like its going to rock some socks off. Personally i think that if you dont plan on actually using the armour in uh "action" 14g maight be a bit heavy, however, not knowing exactly where you'll be using that thickness and the fact that you plan on welding support rods (bloody awesome btw) means that i'd be talking out my hooha.
I can, however being that i do have experience (as well as CyberPaddy66) fighting in armour help give advice on rigging the suit to help it float better and allow easy movement. One resource to definitely check out if you havent already is armourarchive.com
can't wait to see pics
Kerberos