Actually the rag joint system is better than a clam shell to me.
It puts a slight buffer between the engine and drive wheel.
Not much, like .2mm 'give' but something for those hard clutch drops and 9 bolts holding it.
If a clam shell gives it's 3 or 4 bolts spin on the hub and take out spokes.
The thing is, they are just not that hard to install.
1. Put your sprocket on a flat surface and makes sure it's true.
You can never true a warped sprocket and I have probably 15 new ones that were warped right out of the box in my sprocket pile.
2. Get the sprocket bolted in kind of loose, flip your bike over and put the wheel on (or put in a fork in a vice like we do), so you can spin it.
3. There are 2 things to look at...
Side to side wobble, look at it edgewise for this.
And up-down no-center issues, look at the sprocket face for this.
Side to side will throw chain, up and down will cause the chain to get loose, then tight, then loose again.
Adjust your 9 bolts in a star pattern and look as you go.
It also helps to see how much bolt end sticks out on the inside after the nuts are on, keep them close as you go.
Finally, if you get it true horizontal wobble wise but have an issue with vertical up and down, you can put a piece of junk chain in the sprocket and tap it down into place vertically on that.
4. Which way to cup the sprocket.
This depends entirely on where your engine output sprocket is.
The back sprocket has to be in line with it.
415 chain don't bend around fat tires with a sprocket cupped wrong and a tensioner not centered in the true chain line .
That goes for any mount system.
I have
~60 builds with rag sprocket drive and just don't have problems.
Just a side note, they are not rags, those rings are punched out of used tire sidewalls.
That means they are not all the same and they have a slight curve to them.
Done properly and tight they give enough for the spokes and come together to grip as one piece.