Greetings!  I've written to the AMA Safety Coordinator for his thoughts and now I'd like to put this forth to those more knowledgeable than me.  I am writing this seeking recommendations / rules concerning the use of a product specifically Sullivan kevlar cable.  This product is rated at 100 pounds which seems to exceed the requirements written in the scale rules.  I am in the process of building a control line B-29 and although I know that most of types of control line planes use either solid music wire or your stranded cable, I would like your thoughts on using the kevlar cables in place of the other options.  Being as this is a four engine (.25 c.i.) which should end up, I'm guessing, in the 6-10 pound range, ready to fly, I believe the actual pull test will be in the 40-50 pound range.  As such, the kevlar cable would well exceed the appropriate test range.  It would be my intention to use a length of the Sullivan Gold-N-Rod inner sheath to enclose the two leadout cables exiting from the fuselage to the wing tip to minimize the possibilities of fraying and direct handling.  I do not, repeat, do not intend to use the kevlar lines for actual flying, just as leadouts.  Thank you in advance as I look forward to your responses.

 I do not, repeat, do not intend to use the kevlar lines for actual flying, just as leadouts. 
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You WILL be using them for actual flying. That being said, I don't believe the rule book is specific about the material requirements for leadouts, only that the system be strong enough. I am wondering why you would want to do this.