I'd be interested in modifications that people have made to the Novak diagonal holder in order to make collimation easier. I always groan out loud whenever the collimation slips. Tightening the nut to hold the diagonal onto the spider throws it out of alignment since the vanes bend and using a screwdriver to adjust the three screws holding the diagonal tilt (while you are supposed to be looking through the focuser at the same time) is an poor design. At least replacing those screws with knurled knobs would be a major help.
Perhaps there are better diagonal holder/alignment systems?
Brian Drummond