I haven't used the toothbar too much yet, but it has held up to the little playing I have done so far. The shank (or adapter as they seem to be called around here) design is not a problem, it is just that in my case there wasn't much width available for the flat bar because of how the cutting edge was welded on the bucket. There was about 1/4" of space between the adapter and top of the cutting edge (thus the 1/4" flat bar) and if the top of the cutting edge happened to be flush with the rest of the bucket inside, I could have used a 4" or 5" width for extra strength and would not have had to notch it.
If it is possible for you, I would recommend what I did - load your bucket in the back of a pickup and go to some local places that sell teeth and adapters (try calling some heavy equipment dealers, vendors of skid steer equipment or attachments, etc.). The places I went were more than willing to let me take the adapters out to the parking lot and actually try them on my bucket to check the fit. I ended up having to get a size larger than I initially thought I wanted, but after getting it all built, the tooth size is actually about right.
If you have no source for adapters and teeth near you, then I would try an internet search for some manufacturers of said items and email or fax their sales department a description of what you want to do and a clear drawing (with dimensions) of your bucket edge and how you expect the adapter to fit on it. Hopefully they can give you some information of what type of adapter to use.
Here's some terminology I learned while shopping:
Underslung - an adapter similar in shape to what I used, except sort of upside down. The long thick part of the adapter goes under the bucket edge and the little hook part on top.
Flush Mount - an adapter that does not hook over the bucket edge at all. They are sort of like mine but without the bottom hook bit. This might be what you want if you were to build a shallow 'V' out of flat bar to fit over the length of your bucket edge and weld the adapters to that. They are called flush mount because when welded directly to a compatible bucket, the bottom of the teeth are flush with the bottom of the bucket.
Semi Flush Mount - these are what I used. The long thick part is above the bucket edge with a smaller hook under the edge.
Another note: If you don't have a reasonably heavy cutting edge welded or bolted on to your bucket, you will probably want to get one, or use a fairly thick flat bar to weld the teeth to. I can well imagine that hooking a single tooth on something would bend a bucket edge that isn't re-inforced. The cutting edge on my bucket is 3/4" thick, plus the flat bar holding the teeth is about an inch worth of steel to resist bending.
Good luck, and if you want some more specific pictures of my toothbar, or from different angles, let me know - it's no problem.
