I just picked up a set a of CP lower dies made by Hoosier on e-bay and plan on building a hand held planishing hammer. My thought is a tube frame, air hammer and a flat rivet head for a top die. I have some questions for those who have built these before: 1. I want to make the frame light, but if it is too light it won't be good- any recomendations on frame material- I was thinking 3/4 heavy wall tube?? 2. Air hammers- what BPM should I look for? 3. Upper die- is a rivet head good enough or should I spring for the hoosier upper die? (I think it is around $80). 4. Throat size- how deep should I make it? I plan on using this to work on my 34 coupe with extensive roll over roof damage. 5. Lower die holder- what material should I make it out of so my dies don't get stuck in it? If you have not seen the hoosier dies, check them out, they look nice!