The major problem with NiCd's is their fast self discharge rate, unlike modern NiMH cells. They do outperform NiMH in some other respects, though. If you let a NiCd sit for a year, it is killing itself. You need to periodically charge them so they do not over discharge.
Are you aware of the Battery University site? It has a lot of useful and accurate information.
Battery University appears to favor or be specialized in lithium-ion. Not much on Ni-cad. Other sites have very good specs and advice on maximizing life of batteries. They emphasize the need to charge monthly but also the need to deep DISCHARGE and recharge every one to 3 months depending on use of course. So you can't help with a discharge circuit and I'm left with having to needlessly wear out my drill taping the trigger on ???