No, it is most certainly NOT normal. Voltages should climb up nearly instantly and remain steady at all times. There are many things in this power supply known to cause issues, and I remember running into a handful of threads where stability issues were being caused by a specific component that other members were trying to find functional substitutes for. I forget which threads they were, its been years.
So, you're telling me that fluctuating voltage isn't normal? Well that's a start, now let's find the problem! What could go wrong with the power supply?
I'm no expert in electrical circuits, but my tip is on the T3 transformer, last time I checked, it looked kinda fried up.
Then that click-click sector is a bad sector. It needs to be mapped in the bad table. Not sure how you can do that with Mac software, but I know you can do that with PC software. Once all known bad cylinders are stored in the preformatted bad table, that blocks them off from OS tools being able to use it. Then the drive will skip over that sector every time.
Woo, worked out the graphics issue - the monitor didn't like been overclocked that hard from the IIx. It is usually ok at 75hz, but for some reason it wasn't here.
At the moment I've found that it runs at 72hz in 800x600... still technically too fast, but the screen copes.
Just disk and possibly pram issues now! So close! From dead to photoshop in ~3 weeks!