leader butt size
Hi Gotsteel,
being new on the forum it took a while before i found your question. It interested me because i have another problem using RIO's AFS shooting heads. But first about this butt size. Being Flemish i have had the privilege to become friends with Guido Vinck (7 times world champion precision casting) and he taught me that the ideal leader butt size corresponds with the figure of the line weight ... in the metric system!
In your case, using a 6/7 line that would mean using a leader butt of minimum 0.060 cm or 60/°°(#6) and maximum 0.070 or 70/°° (#7) to insure maximal energy transfer. I've done a bit of arithmetics and these diameters coincide with the .026'' you have in mind (.026x2.4 cm = 0.0624 or roughly 0.062 cm or 62/°°). So in my opinion you are spot on. From there you can go on : #8 takes a 80/°° leader butt and so on. On the other end : #4 for example asks for a 40/°° leader butt. I hope this can help you, it sure works for me!
Now for my problem: spey casting with a combination of RIO's 8/9 floating SH (34 gr.), a 10' intermediate polyleader (+/- 3 gr.) and about 10' fluorocarbon leader about half of my casts the whole thing collapses in the air resulting in a heaped leader. I use a Vision DH Catapult 14' #10 (34 gr.) so my line weight seems right (the #9/10 is too heavy weighing 38 gr.)and I've done about everything to get the errors out of my casting technique without result. I must say that i cast consistently in the 100' to 120' range but there's always a few yards of running line left laying at my feet and i don't stop the line by hand at the end of the cast. I wonder if that is the problem: the line collapses due to sudden loss of energy and no significant counter friction. Would that mean that one has to pull off the exact amount of line you want to cast and cast unto the reel to straighten the leader?
Tight lines
Johan