if you see a cold cranking amps rating,, you are looking at the wrong type of battery for RE use.
i know they are sold as deep cycle batteries, but their ability to do so is only marginally better than a car battery, and woefully short of what a true deep cycle can deliver.
i know of no true deep cycle that has a cca rating associated with it.
100, 20 and 8 hour ratings are basically how many amp the battery can deliver
over time.
a 100amp hour battery can deliver 1 amp for 100 hours, 5 amps for 20 hours, about 12 amps for 8 hours,, (more or less), until it is dead. which is not what you want to do anyway,,
myself i would figure on no more than a 50% depth of discharge, before recharging, so each of the previous numbers get cut in half (roughly)
others will explain this better than i have,, surely.
bob g