As far as the discussion goes, I don't think there is any one perfect answer to our dilemma for FEL bucket chain attachments. It was after alot of listening in here that I decided to go with the Angle iron.
I don't see the notches as 'lost stiffness', I look at them as being the real reason for putting the angle iron there in the first place. I see the horizontal stock of the angle iron as a bonus, not the end all of stiffness I may need. Again it's not the perfect answer but it's a great start!
I did not reinforce underneath the bucket top, if I find some appropriate material I may have some welded in there, we'll see.
I have used this quite a bit already and am very pleased. I always try to put the weight towards the edges whenever possible. I love the options 5 slots give me, and have had seen no indication that the chain will 'slip' out the top.
With this setup I can even help out the big boys...