I don't found spare 608 bearings, so I remix the holder for 624zz bearings.
The bearings are fixed with M4x16 screws.
You can use it without the other things.
But I use it with the stockholder to get a level surface.
I you want to see the rotation you can use the 'hand' and fix it with the bayonet lock.
To avoid the spool to slip, stick the stopper at the end of the holder.
The only thing that need support is the lock.
I printed the Holder with adaptive layer due to the thread. (0,17mm - 0,32mm)