I have the Hasselblad version. There must be a hundred articles on these battery holders on the internet. They were not made to be re-celled but can be.
I think the easiest answer for an amateur doing occasional use is just to use alkalines in the holders meant for them. If I had it all to do over again I might do that.
What I did first was to re-cell the rechargeable battery holders with NiMH. This is not recommended (because the charger is not meant for them) but it worked.
Then I found a Quantum Battery 2 and an adapter for this flash, and put a new battery in the Quantum unit. This was the best way overall. Quantums with dead batteries are very inexpensive and you need to be just a little handy with electrical things to replace the batteries.