Just in front of the bridge, about 25% of the way to the first mast pole usually causes big explosions for me (50% of the time). Then again, at 400m range using fast T1's, if you fire a little earlier you'll have plenty of time to get another one off after the impact of the first (assuming <~8 knots speed merchant)
What did you go for in the end? Be interesting to know what happened
