Hi Scott,
Thanks for that info, very helpful. I was wondering about the alternator... I do have the MV Alpha 24/110 Alternator, but I don't know if I have the original or series II regulator.  Best info I can find at the moment says that series II was released around 2013, so most likely I don't have that and will need to upgrade to the Series II or III.

I believe HVD is handled best by avoiding it.  The chargers must be programmed to shutdown before HVD voltage is reached. For example the Relion RB24V50 HVD is 31.2V, whereas fully charged is 29.2V, so chargers can be programmed to shut down at say 29.5.

This can be programmed with the Mastervolt chargers and Series II/III regulators.  If a charger fault causes higher voltage, then as you suggest, its possible that a voltage spike on disconnect will result, possible destroying the faulty charger.  In theory, the other chargers should be shutdown at that stage, which may limit the damage.
When your battery imbalance occurred, did all of your strings disconnect simultaneously? 

I'm hoping to minimise the chance of battery imbalance by using 24V batteries rather than 2x12V pairs. This also provides 8 batteries in parallel, so I suspect it's less likely that all 8 batteries will disconnect simultaneously. All very difficult to predict of course without a test bench.

So the list issue favours AGM's, thanks for that info!

Cheers
Dean
SV Stella A54-154