I have found that pointers and/or separators can be useful in bone reading. An arrow or something similar pointing at a bone or group of bones sends a strong visual message – all but screaming “pay attention here, this is important!” Likewise separators can help your readings by giving a clear message that “this issue is separate from that.” You can use a number of items to represent these concepts. An actual arrow is the most obvious choice and when I started reading a had a small brass arrow. However, it quickly became apparent that it was too small to work well with my shells. It frequently ended up inside of a shell no matter how small the opening. I replaced it with a stone arrowhead. You can get these rather inexpensively if they are of modern manufacture and for a bit more you can have an antique arrowhead. Eventually I replaced the arrow with a small gemstone maintaining the idea, but changing the representation of it.
I learned of separators from one of my teachers* who used sea anemone spines for this purpose and I adopted that practice as well. I have four in my main set and two in my travel set. Both sets have a rather large number of pieces and I find that them very helpful in delineating issues. If you have a small number of bones one pointer/separator might be plenty. Long, slender crystals could be used as well and they have the additional benefit of catching the light making them easy to see.
You could even use a bone for this purpose. There are lots of long, slender bones available and some have easily differentiated ends which can add another level of meaning. A twig is another possibility and they are available in abundance. You might even choose a specific wood or shrub to add additional meaning. And of course there are seashells that are suited to this purpose as well.
You might want to try using pointers and/or separators. Not everyone will find them useful, and for a small set they may be more of a distraction than a help, but for larger sets especially they are worthy of a try.
Happy Bone Reading!
*Gretchen Crilly McKay at Ancestral Wisdom