So, my friend has a bow(yew or osage that his grandpa owned?) Its limbs still work well, however, he is missing a string. I offered to make him a string, but i was planning on getting fastflight. i did a bit of digging around, and found that it is strongly warned against using ff with older bows. sooo, because i was going to use ff with all my new bows that i make, can i use ff with his, or should i just get b50 and use that up before switching to ff?