How much memory does this project have? 16 bits.
How much current does it take to flip a core? 540mA total per each core in this case.
Or 270mA for each selected X and Y wire.
Voltage requirements? +12 Volts for the Sense and Latch circuit.
+13.5 Volts for the X and Y coincident current wires
Can the X and Y current wires be addressed? Yes. A future project is to scale up more memory and include the logic required to address the writing and reading of the cores as well as a automatic Write after Read cycle to preserve the prior memory state.
Is the memory lost when power is removed? No. The cores retain their magnetic state when power is removed. Nonvolatile Memory.
What kind of copper foil is being used? Stained Glass Foiling Tape found in many hobby and craft stores. The foil takes solder quite well but the heat of soldering will weaken the adhesive on smaller pads and they will move around a little until cooled.
Nice to see someone playing with magnetic cores. You might find some elements of interest in an article on one of my pages where many years ago I examined and was amazed by the design for an IBM 1620 core memory. The designers were obviously driven to minimize the number of driver transistors in their hardware design. It took me a while to figure out what was going on, but found it to be quite slick. Here is where you can find it: https://www.angelfire.com/oh3/ebjoew/IBM_1620_Core_Memory.html