1. Dice, when should i use you?
Definition of Anko, is a "story that most actions are decided by dice rolls", as such, you must have two things for an anko, A story, and a die.
As for why Anko seemed to be more fun that vomiting words and creating textwalls, it is because the dice rolls add an uncertainty for the writer and the reader, requiring both sides to think ahead of the progress, and occasionally, leading to weird and bizarre processes and outcomes.
But, not all actions is decided by dice, as a writer you can reserve some so to avoid an absolute bad end, or neglect some that a fact. For example, when writing anko, we won't do a 1d2 roll for each day to decide whether the sun will rise or not (if your story doesn't involve destroying the sun, that is)
As such, think of anko as a tree, with each choice (branch) leading to even more diverse outcomes (twigs), some outcomes may be bad, and some may be good, but everything should be reasonable and reachable
Now, there are several types of dice rolls that i had came across:
Gal-game mode, just like gal-games (erotic or not), there are choices leading to different consequences. In this type of anko, each post will usually be pretty short, and with 1-2 dice rolls situated at the end of each post
RPG mode, mainly having dice rolls for rolling stats, actions and the probability of success. there would usually be a long post, with multiple dice rolls
STG mode, different from RPG, this mode generally consist of a lot of calculations, before deciding the outcome. This type will usually got lots of rolls and numbers with little amount of descriptions
FTG mode, simply doing simple comparison between the rolled value of the attacking side and the defending side, this type is used commonly in combat, but rarely is there an anko using FTG dice rolls for the entire duration (i dare you to proof me wrong XD)
Of course, with more dice rolls, the story gets more randomized and complex, while with less dice rolls, the story might as well become a traditional fiction
Or, in simple terms, as a writer you can freely determine when to use dice or not, but you cannot have an anko that uses dice rolls to decide the character's basic needs, nor an anko which doesn't involve one single dice roll and face the boss
Since dices determines whether a character is vulnerable to effects caused by the actions of others. Counter-application of dice rolls would allow you to create a plot-wise Deus Ex Machina, allowing it to stay invulnerable for the process until you use dice to control its actions