Take your heavy Easton shaft, go the local hardware and find some birch dowels that come in all sizes, if not a perfect fit, sand, or wrap with painters masking tape. It won't cure and you can change things, but if your using standard nocks you probably will have a tough time getting them out, unless you predrill the dowell, you can use a long #6 screw and pull the dowell out if needed. Cut the dowell to fit behind the insert and slide it into the Easton, or graphite of your choice.
Another option.
If they come with UNI Busings and nocks you'll be able to push the dowell out. Or, find a way to make/install a UNI in your shaft. The dowells run about 0.59 cents, lot cheaper than a standard graphite, glass or alum. inside another.
You can pre-weigh everything, and figure out what will work.