It's been a few years since, but looking back quickly I found this on page 18.http://www.askmar.com/ConferenceNotes/S ... uclear.pdf
Mind you it refers to a truncated cube WB7 getting 3-5 times WB6 output, so I'm probably incorrect, though WB6 was built in haste using available material.
Ok, that is what I suspected.
Dr B had different nomenclature at that time than what eventually took place. Dr B's WB7 was NOT the rebuilt WB6 but a differently designed machine. It was the "square plan form" magnet version rather than the round WB6. He thought that the more spherical B field would improve things. Yes, it is interesting that the square plan form magnet would result in a more spherical field, but it does!
Dr B's WB7 has nothing to do with what eventually got called WB7 which was just the rebuilt WB6. Confusion all over the place!
The WB7 that got built should have been simply a more carefully built version of WB6, no more powerful, just less likely to explode. Since we heard nothing of exploding WB7s, I suspect that part worked!
Now, since it may have been able to be driven to higher currents and voltages, it may have achieved higher power (i.e. neutron count) than WB6, but all else being equal, it was the same basic machine.
WB7.1 MAY have had some differences in detail but the coils were surely the same.