As part of a project I am working on, I need to bring up a 4060-based 32.768kHz crystal oscillator circuit and ensure it works without breaking crystals or having cold start issues. I can build a board that has pots on it for adjusting Rs and Rp in the schematic below, but should I just pick load capacitors that match my 12.5pF/1µW 32.768kHz tuning-fork crystal (a rather generic Raltron part, if you're deathly curious), or should I add trimmers for the load capacitors as well? Should I be focusing on only one resistor, or taking the resistor values as givens, for that matter?
Also, are there other tests I should do during the bring-up process besides making sure it starts up at cold temps and works across the supply voltage range I'm dealing with without drifting excessively or frying crystals with excessive drive? I don't have an active or other ultra-high-Z probe, either, so processes based on direct crystal-node measurements are not useful for me.
Bonus: the MC14060 datasheet specifies a 20pF and an 82pF load capacitor (as shown in the schematic above) for making the 4060 oscillate with a watch crystal. Given a 12.5pF watch crystal, though, this seems like an awful lot of load capacitance to me, but my understanding of this sort of thing is somewhat limited. What's going on with their suggestion here?