I was told that the old charger was only putting out about 5 Amp either way and that the 50Amp rating listed on it was to run all the other 12v stuff.
That is not true of the 950. I suspect someone was applying a fact that applied to the old 63xx series Magneteks to the Magnetek 950, but that would be erroneous.
So how many amp charger Do I need to charge them in a timely manner and what kind of charge times should I exspect?
Somewhere is the 50-60A range is probably optimum. A three stage charger will produce slightly faster charge times than a single stage, but the difference is not dramatic. Charge time varies with the starting point state of charge and typically takes 12-15 hours to reach 100%. However, it probably reached 80-85% is just 2.5-3 hours. A 3-stage charger with a high amp capacity gets to that 80% level a bit faster. Beyond that level, it doesn't make much difference what charger is in use because the amp rate is just a trickle.
When the battery voltage drops to about 12.2v (with no active loads), the battery is at the 50-60% charge level.
Randy just suggested a 75Amp charger. I feel that's too big? Won't that kill the battery s or am I missing something?
A higher rate charger simply means it is capable of producing more. It doesn't force more amps in - the battery itself pretty much dictates the amount of amps that actually flow. The charger could force the rate up by applying higher voltage, but that damages the battery and shortens its life, so no quality charger does that. Three (or four) stage chargers carefully adjust the voltage over time so that the battery gets all the amps it can take without overheating or "boiling" it.
So, buying an oversized charger is not harmful, except maybe to your wallet.
Since the charger is also a power converter and supplies 12v power to the RV in addition to charging batteries, some of those amps get used by other 12v devices. However, unless you have a 12v powered fridge running, there probably isn't a sustained demand for more than 5-10 amps of 12v power. The various circuit boards and devices like LP detectors typically consume 2-3 amps continuously, and lighting will add about 1 amp per bulb that it lit. The furnace fan is the only large 12v power draw that runs long enough to have much impact, and that's only when heating. Therefore a 75 amp, 3-stage charger would run all your 12v power equipment and still leave around 55-60A available for charging.