Wattsup,

The S-83 is excellent quality. Universal says 24 mm setback, but there's no standard for measurement. The S-84 has about 35 mm setback. Just try it and see what you need. I agree with Fiets, just try something. If as you suspected you need more setback than the S-83 affords, you should be able to flip it - it's a known good piece.

You have a mix of fit/contact point adjustment issues. Did you by chance write down your saddle location parameters before making any changes? When you install all your new hardware, I would try not to throw out all the bathwater, there might be a baby in there but you don't know where. In other words you don't know which current fit parameters are correct for you. You can see which ones do not match Internet conventions, but the Internet does not know your correct fit. Based on your post #185 , you are aware of the potentially knotty interaction between fit parameters and riding position. I would really try hard to set it to your original positioning, and make small changes, one variable at a time. Or start with Selle's initial positioning guidelines and slowly work it up to a state of comfort. Keep notes, because you might have to go backwards. I found that once I have it good for say, 15 miles, if I go 20 miles it might go bad - more tweaking. Eventually I got it good for 60 which is what I needed, but then next season it was not so good.