I'm trying to figure out the best fluoro-to-braid knot myself. Just exactly what is meant by doubling the braided line? Do you mean double the number of wraps as suggested by http://www.proknot.com/Fishing_Knots/fishing_knots.html, or do you mean make a large loop in the braided line that you then treat as one line when you tie the knot - which leaves you with 4 tag ends instead of 2?
Also Mike, exactly what do you use to measure the breaking strength of your knots? Do you have some scales that keep up with the highest recorded pull/weight or do you just keep an eye on your scales while you pull to see where it is when the knot breaks? I would like to be able to do these kinds of tests myself but currently am limited to tying a different type of knot one each end of my test line and see which one breaks first.
Also have you tried the Albright knot? Just curios as to how it compared if you tried it.
Thanks,
Kelby