Gerardo,
Obviously, the best way to learn aiki-ken and aiki-jo is by learning directly from Saotome sensei or one of his students. I think there must be someone in your area that has a firm grasp of these arts. I think without some frame of reference (having studied with someone who understands) the tapes may be confusing and could be counter productive. I studied both for six or seven years and found them valuable to my understanding of aikido. However, I don't think they are necessary for learning aikido.
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Paul
http://www.aikidokenkyukai.org/usa/ma/ma.index.html