Granted I do not have a heavy duty FEL, 80 Koyker 4' bucket, but that is what I have. I did put plates on the inside of the bucket to prevent bending and nuts pulling through. I only use a 1" nylon strap. If it breaks then I have exceded the limit I want to lift and will find another way. I have not broke the strap yet.
Just to make sure, you are speaking about a "D" and a two bolt bent strap to capture the straight part of the "D". If so then I am using 1/2". I did not plate the top of mine, did not even cross my mind to. That ought to strenghten it up a bit though. I have been pleased with mine. They have done what I need them to do. Paid too much for them at Home Depot, if you have a Northern near by they are far more reasonable.
Granted I do not have a heavy duty FEL, 80 Koyker 4' bucket, but that is what I have. I did put plates on the inside of the bucket to prevent bending and nuts pulling through. I only use a 1" nylon strap. If it breaks then I have exceded the limit I want to lift and will find another way. I have not broke the strap yet.
I would be very leary of a 1" strap except in the lightest of load situations. Breaking the strap to determine the lift limit is completely the wrong idea.
Maybe for you not for me. If my strap breaks then it means I have underestimated the load and will more than likely pull out a chain. My post stated "want to lift" not could lift. When I strap something in or on the lip of the bucket I know where the strap is laying, I am aware that every twist of a strap can cost up to 1/2 the straight pull strength. For me I will break a strap as a heads up about the load.
If you can possibly have it welded, I think you come out ahead welding on a reinforcing plate and a point of attachment for a chain hook.
Straps are fine for securing a load from shifting, but I'm like the others who are leery of using them for lifting. Sunlight, sharp objects, etc. don't wreck chains.
AKwelder brought up a good point in another thread that the bucket might also need to be reinforced at the points where the loader arms attach to the bucket. http://www.tractorbynet.com/forums/customization/131233-help-me-bucket.html
This is what I did, can use chain, straps, rope, pull trailers, boom pole.etc. etc.
JB.