I have learned Colemak with full keyboard, but step by step, one or two keys each time. I don't try any transition methods so I can't say about them.
But it's like Newton principles.
If you learn with full keyboard (one big switch - 17 keys in Colemak), you have to put more mental power on it right from the start, but your road is shorter and fixed from the beginning.
If you learn it gradually, your first step is easier, but the toughness will increase each time, and the road is constantly changing and confusing a bit. Each transition is a mini switch (4 keys at a time).
So 17 or 4 +4+ 4+5. That's all pretty the same I think.