Of course you could just get three section of coiled copper pipe zip tie them together to that the coils are lying side by side as in the original EPGs
then stretch it out like a spring or slinky(tm) and slide the pickup coils along the length of the three pipe coils that are bound together and not so many joints
to solder.
For maximizing flux line cuts consider using six coils surrounding a flexible core of same diameter (remember how 6 pennies will surround a seventh
penny in the middle) and then you will have a symmetrical roundish rope of channels each carrying the magnetic material, Then stretch out
six stranded (hollow cored) super spiral lie a slinky(tm) or spring The technology is like a reverse solenoid with the magnetic core moving and generating
power in pickup coils (similar to a faraday shake flashlight)
