Antrim,
To answer some of your questions, I went with fabco teeth but I had to get them through Werk-Brau. I went with the 23 series Pin on teeth because I wanted the ability to change the teeth if worn. And they do have some preety cool tooth options! I wanted my teeth and adapters to be perfectly flush with the bottom of my cutting edge so I used an adapter that was made for that and does not have the hook for the cutting edge. I gound my 4x1/2" bar stock to match the angle of my cutting edge, drilled it and the cutting edge, Tapped the cutting edge, and bolted down with 5 Grade 8 bolts. The result was a perfect fit!!! As far as spacing went I have a 52" openning on my bucket so the spacing worked out very near 10" on center with 6 teeth. Just a note that I am also going to add a grapple so I wanted an even amount of teeth as I did not want to offset a center tooth. Pics will follow as soon as I get a chance, but I can tell you people are not lying when they tell you these things really help with digging.
total cost for teeth was $130 that is shipping and I have an extra adapter, 3 extra teeth and 6 extra pins. I wanted extra teeth and pins on hand incase one came off but after intallation I am quite sure that will not be a problem. So any one in western New york area interested in them I have a bit extra and it would allow you to test fit.