I really wouldn't worry about which meal is your biggest meal, I don't think it is going to have a serious effect.

The 'breakfast like a king etc.' rule is very useful for people who are carb-sensitive, I've found. For me, it works to eat the most calories (and carbs) early in the day. My meals get smaller and smaller as the day goes on, so by dinner my only carbs are coming from my vegetables, which just reduces my calories by necessity.

That works for me *because* I'm carb sensitive. I don't imagine people who aren't would have to worry about it that much. Lucky you! :D

Another vote for dinner as biggest. Mine is usually a main dish (pasta + meat, ww pizza, chicken, etc.) with lots of veggies. Then follows a little fruit and a cookie or chips for dessert.

I think the trainer's idea is a good one -- but if you have issues about being hungry at night, I think it's just better to do what you need to so that you can stop that.