Most serious indexing requires a custom wheel since no lathes index wheels are divisible by 5, 7, 9 etc. and those odd number are so much more interesting.
Another simple device was one J Paul Fennel showed at a symposium a few years ago. He mounted an aluminum disck on the tail stock side of the spindle.
He cut slots around the edge. He then mounts a hinged piece of metal on the top of the tailstock. This fits into the wheel slot and held it in place.
The advantage of this outboard attachment is that the wheel can be loosend and rotated while the work is secure. This makes lining the indexes up with the wood easy. If you want to leave a feature or remove a defect you can set the first index marks about this feature or if you have several of these you can balance out among them rather easily.
My wife does indexing using big disks off the lathe marked with index lines. She learned this from Al Stirt. She removes the piece from the lathe with or without the chuck attached and sets it on the center of the disk then marks the index lines then puts it back on the lathe. This make lining up the grain with the marks even simpler. If she need to mark top and bottom she can flip the piece over. One advantage of this method is that it is easy to compare several different index wheels like a 9 versus a 7.
happy turning,
Al