Remember that cacti do NOT like having their roots constantly wet. It has been MY experience that not letting the soil of a cactus dry out completely between waterings is to invite root rot. I have killed many a cactus like this. So I have gone to using a mix that is anywhere between 80% and 100% inorganic, depending on the cactus. You can talk about "general" rules for cactus care all day long ... which will be "generally" true ... but you HAVE to remember that SOME cacti have very specific wants regarding their environment. Some will like bright sunlight ALL day long ... and some like partial shade because they sunburn easily. So for each cactus, you have to do the research for what THAT cactus wants.
You say that you have not been collecting succulents for long ... but you already have more plants that I do, and I have been growing/collecting them for years. And from what I hear you say, it seems as though you are doing good research to find out how to take care of your cacti.
Look for my posts, mainly in Member Topics, see what I've got, and If I can help you at all, I will be very glad to. Ask away ...