Amanos and Ramshorn are fine with angels from my own experience, it really depends on the individual. But like what Clive said its best to tackle the cause of the problem. Amanos and Ramshorn together does not eat every type of algae, most algae eaters have their algae that they will like to eat and will only eat those. Once the algae they like to eat are gone, other algae will be left and can grow in. This is why you often see people add lots of different algae eaters in the tank, this can cause problems with your tank if it is already stocked to its capacity especially once the algae are eaten and you're required to supplement the algae eaters with more food. Therefore, its always wise to fix the causes by say lowering the lighting levels or fixing the CO2/flow problems.