Sorry Rob, I don't know how I missed replying to this. But better late than never.
I guess that my idea would be to try to start out with the basics, SpG, NH4,
NO2,
NO3, temp,
pH,
PO4. This is helpful to the beginner and to folks like me who find that conventional wisdom has changed when they re-enter the hobby after years away from it. I know that some of it is covered in the
nitrogen cycle podcasts too. Then build up to the other parameters that a more advanced aquarist might test for like
alk,
Ca, Mg and then Fe, B, K, etc. When and why would you test for each. Should you dose with out testing? You could mention Wildeones bit about reading tests under the proper color of light. If you use a
hydrometer to rinse it after every use with
RO/DI. I could put together some more thoughts if you need, just let me know.