The energy levels would have been a spread, so it would have probably been difficult to get all the energy this way. More likely it would have had to have been ion charge collectors at various discrete voltage levels that could be combined into a common output.
I think Dr Pak was working on a DC transformer to address this issue.
It's been awhile since I looked in on Polywell.
Polywell is the same old High Energy Physics approach to Fusion. What they should do is confine the hydrogen inside a metallic matrix and run the same levels of Ion Beam target research. Smaller number of fusion reactions but more manageable.
https://en.wikipedia.org/wiki/Polywell