You've won 7 consecutive games - and you've only played 7 games? Oh.
I thought I was doing quite well having won 2 of the 3 games I have played, and coming third in the one I didn't win. Your achievement is very impressive

My strategy is slightly different, but mostly the same. I just never drill mines until the very late stages of the game because I don't feel it's worth spending vital drillers in the early or mid-game - drillers that could be use to capture other players' mines. I always drill all my mines in the last 48 hours of the game.
In regard to specialists, I, personally, would say that the navigator is definitely my favourite. It is near invincible. With a simple double course change, it can't be affected by saboteurs, and combined with a large attacking force it is impossible to defend against, because if you reinforce one outpost, the enemy can just navigate the sub to another outpost. Navigator has saved me countless drillers. But overall, I agree with your guide.