so does anybody know if 50-60hz toroid power xfmrs are always steel coil cores? and if the primary should be wound first or second?
If you ask if there are Ni-core power toroids around, the answer is no. For power toroids, iron is nearly always used. There are two different grades if toroid-core iron available - A-grade and B-grade. A-grade is cores wound with one continous piece if iron sheet, B-grade are wound from cutoff's of all sizes (leftovers from production of "A"s).
A-grade is more transfer-efficient and has higher A(l) - but B-grade behaves a bit like a gapped transformer, allowing a tiny bit of DC current before acting up, making it more usable for some of our audio experiments. But B-grade will need more turns to acheive the same inductance, thus might run into problems with winding capacitance.
Cheap toroids are nearly always B-grade, as the price difference in core material is significant.
The mains-part of the toroid power transformers, the primary winding, is located as the inner winding in 99% of the cases (that is, wound first) - probably to protect from mains-power-hazards in case of mechanical damage to the winding.
This makes it relatively easy to unwind or cut the secondary(s), and rewind to what you need.
Jakob E.