Sorry for the late reply to this, I haven't been around much recently.
As someone that has been RPing a former slave character myself, I've tended to treat slavery as per Chained to the Sky. That is, slaves as just the working class laborers for the Amarr. More "free" than what one traditionally considers a slave by the simple fact that when 50% of your society is slaves and they fill the vast majority of blue collar jobs we see in real life, you have to get your mind away from the highly isolated plantation/single estate idea of slavery because it just doesn't work in a heavily populated and technologically advanced society. While plantations and work camps and the like do absolutely exist in Amarr I tend to equate them with lower generation slaves, 1st or 2nd generation, who still have to be 'broken in'. Once they've become sufficiently indoctrinated and integrated into society, the standard of living and freedoms goes up (it's gradually increasing the level of rewards for productive and obedient service, while also reducing the costs of Holder by not having to micromanage as much and engaging slaves in the economy). By the higher generations, you're probably a slave only really in name. Chained to the Sky at least shows them choosing to walk about on their own, go to a bar (that's frequented by commoners as well), order and pay for their own food, etc. And EVE Source talks about even miner slaves getting vacation times which includes unsupervised visits to a nearby major city.
So, how I've RPed it with my slave's background, as a very high generation slave (12 or 13 or so) is that her family had their own (small) house, in a slave/commoner district, with good education, typical working hours (if long, and working even during youth), and a limited form of currency (limited in that it can only be used on "approved" purchases, like food and basic home supplies and personal possessions, rather than anything you want) and ability to shop in normal stores. Still limited choice in the type of education and occupations, as that'd all be based on the needs of the Holder and somewhat by the skillset of the slave.