Dont know the website or article but theres one I made myself.
http://good-times.webshots.com/photo/2436229470102553149QhRwxVheres a side profile of one that I bought.
http://rides.webshots.com/photo/2266564490102553149GPuHnZI would aim at making the total weight around 1.5 to 2 lbs. Anything lighter then 1 lbs is wasting time and over 2 lbs gets heavy real quick.
The one I made in the first pic is from a 90ish Ford F250 so its thick and weighs about 4 lbs. Its friggin heavy but moves the metal fast!!
I use that one to rough stuff up then finesse everything with the one in the second pic which weighs 2 lbs.
I clamped one end in a vise heated it up cherry red then bent it. Heated another spot for the offset. Then I trimmed the area where the handle is down and welded a pipe over it for comfort.
THE MOST IMPORTANT thing to do is dress the surface of the spoon!!!!
Use a high speed grinder with 36 grit to smooth the surface and remove any nicks etc. Then move to 80 grit and continue to about 150 grit to polish the surface. The shiner the slapper surface the shiner the surface on your metal you are repairing which means you can repair the damage easier and faster.
But you NEED to remove any nicks from the slapper's surface otherwise it will print itself into the metal's surface...Eric