All the techniques pretty much fall under two categories, waking up in the dream world, and falling asleep consciously. Within the two categories they're pretty similar in my opinion.

I don't know VILD really but I think it's probably like MILD and all the rest. VILD just relies more on visualisation and imagination which is used in MILD as well. MILD is what you described in your original post by the way. When it comes down to it you're simply imagining/picturing/visualising yourself becoming lucid as long as you possibly can until you fall sleep. Hopefully it will be the very last thing you think about so that suddenly you realise it actually IS a dream.

Adding in the affirmations at the same time is just trying to increase your chances by any means, and it probably does.

How long should you incubate the dream for? The longer the better so don't worry if it takes ages to fall back to sleep. I think you have to do it right before sleep, you can't incubate it today and then hope it works tomorrow night.

Falling asleep consciously, WILD, is definitely very hard to do for the majority of people so probably best to start with a tech like MILD to wake up within the dream first. Simply because you'll probably be successful a lot quicker and won't lose interest.