The manner in which the risers are positioned on the ribs of the boat will keep them from corroding the bottom of the boat. I haven't seen any signs of corrosion around the rivets on the ribs but the situation does exist. I guess when that happens I will have to address it then.
I didn't find them much heavier than the aluminum angle, but you do have to coat any place that you cut with a Rustoleum paint to keep it from rusting. I think I ended up using 4 six foot brackets for the front deck. My biggest concern was money, plus i am not a big fella (147lbs), so...
I finished this build just before summer this year. I am no carpenter or welder, but I managed to make a quality boat out of unconventional items. After all the mods were finished, I spent about $275.00 on materials. The transom was the first to be replaced. The side floatation boxes got cut...